States of Elements

Question 1

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 1

Gas

A gas is a substance that has neither a defined volume nor shape.
Gases have the weakest intermolecular (between molecules) attractions of all the four fundamental states of matter.

Question 2

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 2

Gas

Noble gases include all group 18 elements, such as helium, and are called such for the fact they are all gases under standard conditions and have low reactivity.
One atmosphere pressure (1 atm) is equivalent to about 1.013 bar or 101 kPa (kiloPascals).

Question 4

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 4

Solid

Solids have the strongest intermolecular (‘between molecules’) forces of all the four fundamental states of matter (solid, liquid, gas, plasma).
Particles within solids are closely ‘packed’ and vibrate in place, rather than moving around like particles of liquids or gases.

Question 6

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 6

Solid

Most metals are good conductors of electricity because of metallic bonding and delocalised electrons. These free-flowing charged particles transmit electrical energy efficiently.

Question 7

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 7

Solid

Boron is a metalloid with properties intermediate between metals and nonmetals, such as being a semiconductor and forming crystalline solid structures through covalent bonding of atoms.
Solids have the strongest intermolecular (‘between molecules’) forces of all the four fundamental states of matter (solid, liquid, gas, plasma).

Question 8

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 8

Solid

Carbon has various allotropes, including diamond and graphite, each with distinct properties due to variations in the bonding patterns of carbon atoms.

For example, diamond consists of a tetrahedral arrangement of covalently bonded carbon atoms. In contrast, graphite is made up of hexagonally-arranged carbon atoms forming ‘sheets’ that are layered and held together by weaker Van der Waals forces.

Question 9

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 9

Gas

In an ‘ideal gas’ (a theoretical concept used in calculations), the individual gas molecules exhibit no attractive forces toward each other. This, however, is not a practical effect observed in nature.

Nitrogen gas has two key types of bonding: intramolecular and intermolecular.

• Intramolecular bonding refers to the three covalent bonds shared between two nitrogen atoms, forming the non-polar molecule, N₂.
• Intermolecular attractions are the London dispersion forces between these rapidly moving N₂ molecules as they come into proximity with each other.

Question 10

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 10

Gas

As intermolecular forces rely on molecules being sufficiently close, the rapidly moving and ‘spread apart’ gas molecules have the least optimal conditions for these to occur.

Oxygen gas has two key types of bonding: intramolecular and intermolecular.

• Intramolecular bonding refers to the double covalent bond shared between two oxygen atoms, forming the non-polar molecule, O₂.
• Intermolecular attractions are the London dispersion forces between these rapidly moving O₂ molecules as they come into proximity with each other.

Question 11

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 11

Gas

Halogen gases such as fluorine have very high electronegativities.
A gas is a substance that has neither a defined volume nor shape.

Question 13

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 13

Gas

Gases are less dense than liquids or solids as they have less particles per unit of volume due to their constant, random motion.
Unlike diatomic gases such as hydrogen (H₂), neon exists as unbonded atoms in its gaseous form, making it monatomic instead.

Question 15

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 15

Solid

Although ‘sodium’ is usually thought of as its ‘table salt’ (NaCl) form, elemental sodium is actually a soft, silvery-white solid metal.
Solids have the strongest intermolecular (‘between molecules’) forces of all the four fundamental states of matter (solid, liquid, gas, plasma).

Question 16

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 16

Solid

Because of the nature of metallic bonding and the delocalized electrons involved, most metals are good conductors of electricity. This is because delocalized electrons are free-flowing charged particles able to transmit electrical energy from one point to another.

Group 2 metals, also known as alkaline-earth metals, have a stable oxidation state of +2. This means that for each magnesium atom in a solid structure, it contributes two delocalized electrons.

Question 17

Identify the state under standard conditions.

(or Aluminum)

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 17

Solid

Aluminium’s most common oxidation state is +3.

During metallic bonding, it can be thought of as Al³⁺ ions surrounded by a sea of delocalised electrons, with each atom contributing three to this ‘pool’.
Aluminium (Al) has a strong affinity for oxygen, and so will form a thin layer of aluminium oxide (Al₂O₃) on its outer layer, making it highly resistant to corrosion.

Question 18

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 18

Solid

Solids have a fixed shape and volume, and so don’t morph like liquids to fit the container they’re in.
Silicon is a metalloid with properties intermediate between metals and nonmetals, such as being a semiconductor and forming crystalline solid structures through covalent bonding of atoms.

Question 19

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 19

Solid

Phosphorus exists in various allotropes, including white, red, and black phosphorus, with different physical and chemical properties.
In the white P allotrope, it exists as individual tetra-atomic molecules. No atom has a double covalent bond with any other, meaning every phosphorus has a lone pair of electrons, making it highly reactive.

In red P, these tetra-atomic molecules form a polymeric structure, making it far less reactive.

Question 20

Identify the state under standard conditions.

(or Sulfur)

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 20

Solid

Sulfur has five main allotropes: α-S (orthorhombic), β-S (monoclinic), S₂, S₃, cyclo-S₈.

The rhombic allotrope of sulfur is the most stable and is described as an octahedral shape, whilst the monoclinic form of sulfur is described as ‘needle-shaped’ crystal structure.
Solids have the lowest average kinetic energy of all the four fundamental states of matter.

Question 21

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 21

Gas

Gases have the highest average kinetic energy of all the four fundamental states of matter.
In its gaseous form, chlorine exists as discrete Cl₂ molecules with very weak intermolecular forces occurring between them.

Question 22

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 22

Gas

Gases can be compressed far more easily than liquids or solids due to the high levels of empty space between gas molecules.
Gases are less dense than liquids or solids as they have less particles per unit of volume due to their constant, random motion.

Question 23

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 23

Solid

Because of the nature of metallic bonding and the delocalised electrons involved, most metals are good conductors of electricity.

This is because delocalised electrons are free-flowing charged particles able to transmit electrical energy from one point to another.
Group 1 metals, also known as alkaline-earth metals, have a stable oxidation state of +1.

This means for each potassium atom in a solid structure, it contributes one delocalised electron.

Question 24

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 24

Solid

Group 2 metals, also known as alkaline-earth metals, have a stable oxidation state of +2.

This means for each calcium atom in a solid structure, it contributes two delocalised electrons.
Metals such as calcium are described as being ‘soft’.

This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals.

Question 25

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 25

Solid

The two major categories of solid substances are crystalline and amorphous. Some elements may have different allotropes that exist in either of these forms.

Most metals are crystalline in their solid state.
The crystalline structure of scandium is ‘hexagonal close-packed’ (hcp).

Question 26

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 26

Solid

Titanium has a high strength-to-weight ratio.
The size, mass, and arrangement of atoms in a solid determines its density.

Question 27

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 27

Solid

The crystal structure of vanadium is ‘body-centred cubic’ (bcc).
Solids have the lowest average kinetic energy of all the four fundamental states of matter.

Question 28

Identify the state under standard conditions.

Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 28

Solid

Chromium’s crystal structure is ‘body-centred cubic’ (bcc).
Chromium (Cr) is a solid under standard conditions. It is a transition metal commonly used in the manufacturing of stainless steel.

Question 29

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 29

**Solid** ## Footnote Brittle metals such as manganese will crack more easily when they are put under stress (i.e. force is applied to them). Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in.

Question 30

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 30

**Solid** ## Footnote Depending on the temperature, iron's crystal structure will either be 'body-centred cubic' (bcc) or 'face-centred cubic' (fcc). Because of the nature of metallic bonding and the *delocalised electrons* involved, most metals are *good conductors* of electricity. This is because delocalised electrons are *free-flowing charged particles* able to transmit electrical energy from one point to another.

Question 31

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 31

**Solid** ## Footnote Cobalt has two crystallographic structures: hexagonal close-packed (hcp) and face-centred cubic (fcc). The presence of delocalised electrons in a metal allow for the transmission of light (electromagnetic energy) and so solids such as cobalt appear *lustrous*.

Question 32

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 32

**Solid** ## Footnote Nickel has one crystallographic structure: face-centred cubic (fcc). Solids have the strongest *intermolecular* ('between molecules') forces of all the four fundamental states of matter (solid, liquid, gas, plasma).

Question 33

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 33

**Solid** ## Footnote Copper has one crystallographic structure: face-centred cubic (fcc). The ability of atoms to slide past one another into new configurations without breaking their metallic bonding gives rise to metals such as copper being *ductile* (able to be drawn into wire).

Question 34

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 34

**Solid** ## Footnote Metals such as zinc *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen. Zinc has one crystallographic structure at room temperature: hexagonal close-packed (hcp).

Question 35

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 35

**Solid** ## Footnote Metals such as gallium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals. Metals such as gallium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals.

Question 36

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 36

**Solid** ## Footnote Germanium has two key allotropes, α-Ge and ß-Ge, which exist under different conditions to each other. Brittle metalloids such as germanium will crack more easily when they are put under stress (i.e. force is applied to them).

Question 37

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 37

**Solid** ## Footnote Arsenic has three key allotropes; grey, yellow, and black. Their arrangements of atoms are layered, tetrahedral, and amorphous respectively. Arsenic's 'grey' allotropic form is its most stable at room temperature, and a good conductor of electricity.

Question 38

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 38

**Solid** ## Footnote Selenium has three key allotropes; grey, red, and black. It's two key physical forms are a powder and a metallic structure.

Question 39

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 39

**Liquid** ## Footnote Liquids will move to fit the container they're in due to the fact the particles are free-flowing, but are essentially incompressible (will not change volume or density when pressure is applied). *Viscosity* is a property of liquids which describes their resistance to changing shape or opposition to flow.

Question 40

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 40

**Gas** ## Footnote Gases can be compressed far more easily than liquids or solids due to the high levels of empty space between gas molecules. It has the highest average kinetic energy of all the four fundamental states of matter.

Question 41

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 41

**Solid** ## Footnote Rubidium has one crystallographic structure: body-centred cubic (bcc). Metals such as rubidium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals.

Question 42

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 42

**Solid** ## Footnote Solid strontium has a face-centred cubic (fcc) crystal structure. Density and the relative 'hardness' of a metal are two different concepts. It is a measure of mass per volume, while hardness is a substance's ability to resist deformation.

Question 43

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 43

**Solid** ## Footnote Yttrium, much like many other metals is described as being 'soft'. This means that it is *malleable* (able to be reshaped with little force and without cracking or shattering). Yttrium's most common oxidation state is +3, and so in metallic bonding, it can be thought of as Y³⁺ ions surrounded by a sea of delocalised electrons, with each atom contributing three to this 'pool'.

Question 44

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 44

**Solid** ## Footnote Zirconium is described as being a 'hard' metal. This means that it has a higher resistance to surface-level deformation. Zirconium (Zr) has a strong affinity for oxygen, and so will form a thin layer of zirconium oxide (ZrO₂) on its outer layer, making it highly resistant to corrosion.

Question 45

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 45

**Solid** ## Footnote Niobium (Nb) has one crystallographic structure: body-centred cubic (bcc). Niobium (Nb) has a relatively strong affinity for oxygen, and so will form a thin layer of aluminium oxide (Nb₂O₅) on its outer layer, making it highly resistant to corrosion.

Question 46

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 46

**Solid** ## Footnote The presence of delocalised electrons in a metal allow for the transmission of light (electromagnetic energy) and so solids such as molybdenum appear *lustrous*. The majority of metals, like molybdenum, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead.

Question 47

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 47

**Solid** | (Synthetic) ## Footnote Technetium has one crystallographic structure: hexagonal close-packed (hcp). The majority of metals, like technetium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead.

Question 48

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 48

**Solid** ## Footnote Ruthenium has one crystallographic structure: hexagonal close-packed (hcp). The presence of delocalised electrons in a metal allow for the transmission of light (electromagnetic energy) and so solids such as ruthenium appear *lustrous*.

Question 49

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 49

**Solid** ## Footnote The majority of metals, like rhodium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead. Rhodium is described as being a 'hard' metal. This means that it has a higher resistance to surface-level deformation.

Question 50

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 50

**Solid** ## Footnote Palladium is part of the 'noble metals' and so is resistant to oxidation and the effects of many corrosive substances. Under standard conditions, palladium's crystal structure is face-centred cubic (fcc).

Question 51

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 51

**Solid** ## Footnote Silver has one key crystallographic structure under standard conditions: face-centred cubic (fcc). Silver tarnishes in air due to reaction of sulfur compounds on the surface, resulting in a black silver sulfide.

Question 52

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 52

**Solid** ## Footnote Cadmium has one key crystallographic structure under standard conditions: hexagonal close-packed (hcp). The size, mass and arrangement of atoms in a solid determines its density.

Question 53

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 53

**Solid** ## Footnote Indium, much like many other metals is described as being 'soft'. This means that it is *malleable* (able to be reshaped with little force and without cracking or shattering). Because of the nature of metallic bonding and the *delocalised electrons* involved, most metals are *good conductors* of electricity. This is because delocalised electrons are *free-flowing charged particles* able to transmit electrical energy from one point to another.

Question 54

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 54

**Solid** ## Footnote Tin has three key allotropes; white, grey, and rhombic. The arrangements of atoms in white and grey tin are tetragonal and amorphous respectively. Below 13 °C, tin converts to its amorphous grey powder form.

Question 55

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 55

**Solid** ## Footnote Antimony is often classified as having one stable allotrope (white) and three metastable allotropes (yellow, black, and explosive). Under standard conditions, antimony is found in its most stable, metallic form.

Question 56

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 56

**Solid** ## Footnote The two major categories of solid substances are crystalline and amorphous. Some elements may have different allotropes that exist as either of these, such as tellurium, which has a crystalline and a grey amorphous form. Solids have the lowest average kinetic energy of all the four fundamental states of matter.

Question 57

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 57

**Solid** ## Footnote Despite being a halogen element, iodine is in fact a solid substance under standard conditions, and appears as shiny and black with a crystalline structure. Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in.

Question 58

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 58

**Gas** ## Footnote Gases are less dense than liquids or solids as they have less particles per unit of volume due to their constant, random motion.

Question 59

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 59

**Solid** ## Footnote Group 1 metals, also known as alkali metals, have a stable oxidation state of +1. This means for each caesium atom in a solid structure, it contributes one delocalised electron. Caesium's crystal structure is described as a 'primitive cubic lattice'.

Question 60

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 60

**Solid** ## Footnote Group 2 metals, also known as alkaline-earth metals, have a stable oxidation state of +2. This means for each barium atom in a solid structure, it contributes two delocalised electrons. Metals such as barium *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, forming barium oxide (BaO).

Question 61

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 61

**Solid** ## Footnote Under these conditions, lanthanum's crystal structure exists as hexagonal close-packed (hcp). Some metals such as lanthanum rapidly *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, forming lanthanum oxide (La₂O₃).

Question 62

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 62

**Solid** ## Footnote Some metals such as cerium *tarnish* easily in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, forming cerium oxide (CeO₂). Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in.

Question 63

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 63

**Solid** ## Footnote Metals such as praseodymium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals. The majority of metals, like praseodymium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead.

Question 64

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 64

**Solid** ## Footnote Some metals, such as neodymium, rapidly *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, forming neodymium oxide (Nd₂O₃). Under these conditions, the crystal structure of neodymium is double hexagonal close-packed (dhcp).

Question 65

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 65

**Solid** | (Synthetic) ## Footnote Under these conditions, the crystal structure of promethium is double hexagonal close-packed (dhcp). Solids have the strongest *intermolecular* ('between molecules') forces of all the four fundamental states of matter (solid, liquid, gas, plasma).

Question 66

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 66

**Solid** ## Footnote The majority of metals, like samarium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead. Under these conditions, the crystal structure of samarium is rhombohedral.

Question 67

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 67

**Solid** ## Footnote Some metals such as europium rapidly *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, forming europium oxide (Eu₂O₃). Under these conditions, the crystal structure of europium is body-centred cubic (bcc).

Question 68

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 68

**Solid** ## Footnote Metals such as gadolinium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals. Under these conditions, the crystal structure of gadolinium is hexagonal close-packed (hcp).

Question 69

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 69

**Solid** ## Footnote Under these conditions, the crystal structure of terbium is hexagonal close-packed (hcp). Terbium, much like many other metals is described as being 'soft'. This means that it is *malleable* (able to be reshaped with little force and without cracking or shattering).

Question 70

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 70

**Solid** ## Footnote Under these conditions, the crystal structure of dysprosium is hexagonal close-packed (hcp). The presence of delocalised electrons in a metal allows for the transmission of light (electromagnetic energy) and so solids such as dysprosium appear *lustrous*.

Question 71

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 71

**Solid** ## Footnote Under these conditions, the crystal structure of dysprosium is hexagonal close-packed (hcp). The majority of metals, like holmium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead.

Question 72

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 72

**Solid** ## Footnote Under these conditions, the crystal structure of dysprosium is hexagonal close-packed (hcp). Metals such as erbium are described as being 'soft'. This relates to the fact that the force required to cause layers of atoms to slide past each other is comparatively lower in these metals.

Question 73

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 73

**Solid** ## Footnote Under these conditions, the crystal structure of dysprosium is hexagonal close-packed (hcp). Solids have the lowest average kinetic energy of all the four fundamental states of matter.

Question 74

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 74

**Solid** ## Footnote Under these conditions, unlike many other lanthanide metals, the crystal structure of ytterbium is face-centred cubic (fcc). Ytterbium slowly oxidises in air to form a protective layer of ytterbium oxide (Yb₂O₃).

Question 75

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 75

**Solid** ## Footnote Under these conditions, the crystal structure of lutetium is hexagonal close-packed (hcp). Lutetium is described as being a 'hard' metal. This means that it has a higher resistance to surface-level deformation.

Question 76

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 76

**Solid** ## Footnote Hafnium forms a dense oxide film (HfO₂) on its surface that makes it resistant to corrosion. The ability of atoms to slide past one another into new configurations without breaking their metallic bonding gives rise to metals such as hafnium being *ductile* (able to be drawn into wire).

Question 77

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 77

**Solid** ## Footnote Under these conditions, the crystal structure of tantalum is body-centred cubic (bcc). Tantalum forms an oxide film (Ta₂O₅) on its surface which helps give rise to its extreme corrosion resistant properties in aggressive media.

Question 78

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 78

**Solid** ## Footnote Under these conditions, the crystal structure of tungsten is body-centred cubic (bcc). The presence of delocalised electrons in a metal allows for the transmission of light (electromagnetic energy) and so solids such as tungsten appear *lustrous*.

Question 79

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 79

**Solid** ## Footnote The size, mass and arrangement of atoms in a solid determines its density. The metallic bond energy of rhenium means that it has the third-highest melting point of all 118 elements, with tungsten being the only other metallic element with a higher value.

Question 80

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 80

**Solid** ## Footnote Under these conditions, the crystal structure of osmium is hexagonal close-packed (hcp). Osmium is the most dense metal of the periodic table, but note that density and the relative 'hardness' of a metal are two different concepts. Density is a measure of mass per volume, while hardness is a substance's ability to resist deformation.

Question 81

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 81

**Solid** ## Footnote Iridium is described as being a 'hard' metal. This means that it has a higher resistance to surface-level deformation. Iridium is part of the 'noble metals' and so is resistant to oxidation and the effects of many corrosive substances. This list also includes gold, silver, osmium, rhodium, ruthenium, platinum, and palladium.

Question 82

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 82

**Solid** ## Footnote Under these conditions, the crystal structure of platinum is face-centred cubic (fcc). Platinum is part of the 'noble metals' and so is resistant to oxidation and the effects of many corrosive substances. This list also includes gold, silver, osmium, rhodium, ruthenium, iridium, and palladium.

Question 83

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 83

**Solid** ## Footnote Gold is part of the 'noble metals' and so is resistant to oxidation and the effects of many corrosive substances. This list also includes iridium, silver, osmium, rhodium, ruthenium, platinum, and palladium. Due to relativistic effects, gold exhibits a yellow coloration unlike the vast majority of metals that are silver instead. It absorbs wavelengths within the blue color range and reflects those within the yellow range.

Question 84

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 84

**Liquid** ## Footnote The particles within a liquid such as mercury are able to flow freely past each other, but are unable to increase or decrease intermolecular bond distances. This leads to liquids morphing to fit the container they're in. Viscosity and density are fluid characteristics with no direct relationship. Viscosity depends on intermolecular forces, while density depends on the number of particles per unit volume.

Question 85

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 85

**Solid** ## Footnote Under these conditions, the crystal structure of thallium is hexagonal close-packed (hcp). Metals such as thallium *tarnish* easily in air. This is the thin layer of non-protective corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen, known as thallium oxide (Tl₂O, but there are other forms depending on the oxidation state of Tl).

Question 86

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 86

**Solid** ## Footnote Under these conditions, the crystal structure of lead is face-centred cubic (fcc). Lead, much like many other metals is described as being 'soft'. This means that it is *malleable* (able to be reshaped with little force and without cracking or shattering), and lead can be worked into sheets.

Question 87

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 87

**Solid** ## Footnote The reason bismuth appears to have an array of colors (similar to a soap bubble) is due to the oxide layer that forms on its surface. Otherwise, bismuth is a silver-white metal. The size, mass and arrangement of atoms in a solid determines its density, and bismuth rates highly on this measure.

Question 88

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 88

**Solid** ## Footnote Polonium has two key allotropes (α-Po and β-Po), both of which are metallic. Under standard conditions, it exists in the α-Po form with a cubic crystal structure, and converts to β-Po (rhombohedral) at temperatures above 36 °C. Because of the nature of metallic bonding and the *delocalised electrons* involved, most metals are *good conductors* of electricity. This is because delocalised electrons are *free-flowing charged particles* able to transmit electrical energy from one point to another.

Question 89

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 89

**Solid** | (Mostly synthetic) ## Footnote The crystal structure of astatine is unknown due to its radioactivity and short half-life. Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in.

Question 90

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 90

**Gas** ## Footnote In an 'ideal gas' (a theoretical notion used in calculations), the individual gas molecules exhibit no attractive forces toward each other. This however is not a practical effect observed in nature. Gases are less dense than liquids or solids as they have less particles per unit of volume due to their constant, random motion.

Question 91

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 91

**Solid** | (Mostly synthetic) ## Footnote The extrapolated crystal structure of francium is body-centred cubic (bcc). Group 1 metals, also known as alkali metals, have a stable oxidation state of +1. This means for each francium atom in a solid structure, it contributes one delocalised electron.

Question 92

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 92

**Solid** ## Footnote Under these conditions, the crystal structure of radium is body-centred cubic (bcc), much like other barium and the alkali metals. Density and the relative 'hardness' of a metal are two different concepts. Density is a measure of mass per volume, while hardness is a substance's ability to resist deformation.

Question 93

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 93

**Solid** ## Footnote Under these conditions, the crystal structure of actinium is face-centred cubic (fcc). Actinium, much like many other metals is described as being 'soft'. This means that it is *malleable* (able to be reshaped with little force and without cracking or shattering).

Question 94

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 94

**Solid** ## Footnote Under these conditions, the crystal structure of thorium is face-centred cubic (fcc). The majority of metals, like thorium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead.

Question 95

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 95

**Solid** ## Footnote Under these conditions, protactinium has a body-centred tetragonal lattice structure. The presence of delocalised electrons in a metal allows for the transmission of light (electromagnetic energy) and so solids such as protactinium appear *lustrous*.

Question 96

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 96

**Solid** ## Footnote Under these conditions, uranium has an orthorhombic crystal lattice structure. Solids have the lowest average kinetic energy of all the four fundamental states of matter.

Question 97

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 97

**Solid** ## Footnote Ionic solids are similar to metallic solids in the sense that they both have crystal lattice structures. However, ionic solids are made up of alternating anions and cations, while metallic solids comprise metal cations surrounded by a sea of delocalised electrons. Neptunium is a metallic solid. Neptunium has a *monoclinic* crystal structure, meaning it is described by vectors of unequal lengths.

Question 98

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 98

**Solid** | (Mostly synthetic) ## Footnote The majority of metals, like plutonium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead. Plutonium has six different allotropes, lpha (α), beta (β), gamma (γ), delta (δ), delta prime (δ') and epsilon (ε). It forms a seventh phase (zeta, ζ) under high temperature and a limited pressure range.

Question 99

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 99

**Solid** | (Mostly synthetic) ## Footnote The presence of delocalised electrons in a metal allows for the transmission of light (electromagnetic energy) and so solids such as americium appear *lustrous*. Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in.

Question 100

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 100

**Solid** | (Mostly synthetic) ## Footnote Under these conditions, the crystal structure of curium is double hexagonal close-packed (dhcp). Metals such as curium rapidly *tarnish* in air. This is the thin layer of corrosion that forms on the surface of a metal when its atoms react with surrounding oxygen.

Question 101

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 101

**Solid** | (Mostly synthetic) ## Footnote The majority of metals, like berkelium, appear to have a 'silvery' color due to the fact they do not absorb many wavelengths of incident light and so most of it is reflected instead. Berkelium has been found to exhibit two stable crystallographic modifications: face-centred cubic (fcc) and double hexagonal closest packed (dhcp).

Question 102

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 102

**Solid** | (Mostly synthetic) ## Footnote Ionic and metallic solids both have crystal lattice structures. Ionic solids consist of alternating anions and cations, while metallic solids have metal cations surrounded by delocalized electrons. Californium is a metallic solid. Solids can be crystalline or amorphous, and some elements have different allotropes that can exist in either form.

Question 103

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 103

**Solid** | (Synthetic) ## Footnote Solids have a fixed shape and volume, and so don't morph like liquids to fit the container they're in. They have the lowest average kinetic energy of all the four fundamental states of matter.

Question 104

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 104

**Solid** | (Synthetic) ## Footnote Solids have the strongest *intermolecular* ('between molecules') forces of all the four fundamental states of matter (solid, liquid, gas, plasma). The size, mass and arrangement of atoms in a solid determines its density.

Question 105

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 105

**Solid** | (Synthetic) ## Footnote There exists only predictions of mendelevium's crystal structure as very little has ever been synthesised. Scientists can only predict the appearance of mendelevium, as only a few atoms of it have ever been produced.

Question 106

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 106

**Solid** | (Synthetic) ## Footnote There exists only predictions of nobelium's crystal structure as very little has ever been synthesised. Scientists can only predict the appearance of nobelium, as only minute quantities of it have ever been produced.

Question 107

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 107

**Solid** | (Synthetic) ## Footnote There are only predictions of lawrencium's crystal structure, as very little has ever been synthesized. Scientists can only predict the appearance of lawrencium, as only minute quantities have ever been produced.

Question 108

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 108

**Unknown** | (Synthetic) ## Footnote There are only predictions of rutherfordium's crystal structure, as very little has ever been synthesized. It is hypothesized to be hexagonal close-packed (hcp). Because rutherfordium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 109

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 109

**Unknown** | (Synthetic) ## Footnote There are only predictions of dubnium's crystal structure, as very little has ever been synthesized. Because dubnium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 110

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 110

**Unknown** | (Synthetic) ## Footnote There are only predictions of seaborgium's crystal structure, as very little has ever been synthesized. Because seaborgium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 111

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 111

**Unknown** | (Synthetic) ## Footnote There are only predictions of bohrium's crystal structure, as very little has ever been synthesized. Because bohrium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 112

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 112

**Unknown** | (Synthetic) ## Footnote There are only predictions of hassium's crystal structure, as very little has ever been synthesized. Because hassium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 113

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 113

**Unknown** | (Synthetic) ## Footnote There are only predictions of meitnerium's crystal structure, as very little has ever been synthesized. Because meitnerium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 114

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 114

**Unknown** | (Synthetic) ## Footnote There are only predictions of darmstadtium's crystal structure, as very little has ever been synthesized. Because darmstadtium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 115

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 115

**Unknown** | (Synthetic) ## Footnote There are only predictions of roentgenium's crystal structure, as very little has ever been synthesized. Because roentgenium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 116

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 116

**Unknown** | (Synthetic) ## Footnote There are only predictions of copernicium's crystal structure, as very little has ever been synthesized. Because copernicium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 117

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 117

**Unknown** | (Synthetic) ## Footnote There are only predictions of nihonium's crystal structure, as very little has ever been synthesized. Because nihonium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 118

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 118

**Unknown** | (Synthetic) ## Footnote There are only predictions of flerovium's crystal structure, as very little has ever been synthesized. Because flerovium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 119

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 119

**Unknown** | (Synthetic) ## Footnote There are only predictions of moscovium's crystal structure, as very little has ever been synthesized. Because moscovium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 120

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 120

**Unknown** | (Synthetic) ## Footnote There are only predictions of livermorium's crystal structure, as very little has ever been synthesized. Because livermorium has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 121

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 121

**Unknown** | (Synthetic) ## Footnote There are only predictions of tennessine's crystal structure, as very little has ever been synthesized. Because tennessine has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.

Question 122

# Identify the state under standard conditions. ## Footnote Standard conditions are defined as 25.0 °C and one atmosphere pressure.

Answer 122

**Unknown** | (Synthetic) ## Footnote There are only predictions of oganesson's crystal structure, as very little has ever been synthesized. Because oganesson has only unstable isotopes and so little has been produced, its exact chemistry and appearance are unknown.