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Atoms, Elements and Compunds Flashcards

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1
Q

What are all substances made up of?

A

All substances are made up of tiny particles of matter called atoms.

Keywords: Atoms, particles

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2
Q

What are all subatomic particles?

A

Subatomic particles are the tiny particles that make up an atom.
There are three main types:

Protons (positive charge)

Neutrons (no charge)

Electrons (negative charge)

Keywords: charge

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3
Q

What subatomic particles are found in the nucleus?

A

Protons and neutrons

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4
Q

Where are electrons located in an atom?

A

Electrons move around the nucleus in orbital paths called the electron shells or energy levels.

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5
Q

How much of an atom’s weight comes from electrons?

A

Electrons contribute almost none of an atom’s weight — less than 0.01%.

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6
Q

Where is most of an atom’s mass located?

A

Almost all of an atom’s mass is found in the nucleus, which contains protons and neutrons.

Keywords: Protons, neutrons

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7
Q

What is a relative atomic mass unit (amu or u)?

A

A relative atomic mass unit (also called atomic mass unit or amu/u) is a unit used to express the mass of atoms and subatomic particles.
It is defined as 1/12 the mass of a carbon-12 atom.

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8
Q

Which element is used as a standard for relative atomic mass?

A

Carbon-12 is used as the standard.
1 atomic mass unit (amu) is defined as 1/12 the mass of a carbon-12 atom.

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9
Q

What is the unit of relative atomic mass?

A

Relative atomic mass has no unit.

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10
Q

What is the atomic number of an element?

A

The atomic number is the number of protons in the nucleus of an atom.

It determines the identity of an element and its position on the periodic table.

For example, Hydrogen has an atomic number of 1 (1 proton), and Oxygen has an atomic number of 8 (8 protons).

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11
Q

What is the symbol for atomic number?

A

Z

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12
Q

What is a neutral atom?

A

A neutral atom is an atom where the number of protons (positive charge) is equal to the number of electrons (negative charge).
This balance of charges makes the atom electrically neutral because the positive and negative charges cancel each other out.

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13
Q

How many electrons are present in a neutral atom with 5 protons?

A

5

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14
Q

What does the number of electrons in a neutral atom tell you about its position on the periodic table?

A

In a neutral atom, the number of electrons = number of protons (atomic number).
This helps determine the atom’s:

Period (row) — based on the number of electron shells

Group (column) — based on the number of electrons in the outermost shell (valence electrons)

So, the number of electrons helps identify the element’s position and chemical properties.

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15
Q

What is the mass number of an atom?

A

The mass number is the total number of protons and neutrons in the nucleus of an atom.

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16
Q

What is the symbol for mass number?

A

A

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17
Q

How do you write atomic notation using mass number and atomic number?

A

Atomic notation shows an element’s symbol with its mass number (A) and atomic number (Z):
z
X
A
​​
A = mass number (protons + neutrons)

Z = atomic number (protons)

X = chemical symbol

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18
Q

What are nucleons?

A

Nucleons are the particles found in the nucleus of an atom:

Protons (positively charged)

Neutrons (no charge)

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19
Q

What is the relationship between nucleons and mass number?

A

The total number of nucleons (protons and neutrons) in an atom is equal to the mass number (A) of the atom.

Mass number (A) = Number of protons + Number of neutrons

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20
Q

Which group do noble gases belong to on the periodic table?

A

Group VIII but now called Group 18 (formerly Group 0 or Group VIII).

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21
Q

Why are Group 8 (now group 18 noble gases) elements very stable?

A

Because they have a full outer electron shell, which makes them chemically unreactive and very stable.

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22
Q

How is the number of outer shell electrons related to the group number in the periodic table?

A

The group number equals the number of outer shell electrons.

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23
Q

What does the period number in the periodic table tell you about an atom?

A

The period number equals the number of occupied electron shells in an atom.

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24
Q

What is the definition of an isotope?

A

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

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25
Why do isotopes of the same element have the same chemical properties?
Isotopes have the same number of electrons and thus the same electron configuration, which gives them identical chemical properties.
26
How are metal atoms held together in a metal?
Metal atoms are held strongly together by metallic bonding in a giant metallic lattice, where delocalized electrons move freely, allowing metals to conduct electricity and heat.
27
What happens to metal atoms within a metallic lattice?
Metal atoms lose their outer electrons, forming positive ions. The lost electrons become delocalized and move freely through the lattice, creating a strong electrostatic attraction between the ions and electrons.
28
What are delocalized electrons?
Delocalized electrons are electrons that are not bound to a single atom and can move freely throughout the metallic lattice. They come from the outer shells of metal atoms and allow metals to conduct electricity and heat.
29
What are the main physical properties of metals?
Good conductors of electricity Good conductors of heat Malleable (can be hammered into shape) Ductile (can be drawn into wires) High melting and boiling points Strong and dense Shiny (lustrous)
30
Why are metals good conductors of electricity and heat?
Because they have delocalized electrons that move freely and transfer energy quickly through the lattice.
31
Why are metals malleable and ductile?
Layers of metal ions can slide over each other without breaking the metallic bond, thanks to the presence of delocalized electrons.
32
Why do metals have high melting and boiling points?
Because of the strong electrostatic attraction between the positive metal ions and the sea of delocalized electrons, which requires a lot of energy to break.
33
What is an ion?
An ion is an atom or molecule that has gained or lost electrons, giving it an electric charge. Losing electrons = positive ion (cation) Gaining electrons = negative ion (anion)
34
Why do elements form ions?
Elements form ions to achieve a full outer shell of electrons, which makes them more stable. Metals lose electrons to form positive ions (cations) Non-metals gain electrons to form negative ions (anions)
35
What happens when metals lose electrons?
All metals can lose electrons and become positively charged ions known as cations.
36
What happens when non-metals gain electrons?
Non-metals gain electrons and become negatively charged ions known as anions.
37
What happens when metals react with non-metals?
They form ionic compounds. Metals lose electrons to form cations, and non-metals gain electrons to form anions. These oppositely charged ions attract each other strongly.
38
What holds positive and negative ions together in an ionic compound?
Strong electrostatic forces of attraction between oppositely charged ions.
39
What is an ionic bond?
An ionic bond is the force of attraction between oppositely charged ions in an ionic compound.
40
What are dot and cross diagrams?
Dot and cross diagrams show the arrangement of outer shell electrons in an ionic or covalent compound (or element). Dots and crosses represent electrons from different atoms.
41
What type of structure do ionic compounds have?
Ionic compounds have a giant lattice structure, where positive and negative ions are arranged in a regular, repeating pattern held together by strong electrostatic forces.
42
How are the ions arranged in a giant ionic lattice?
The ions are arranged in an ordered and repeating pattern, creating a regular structure that maximizes the attraction between oppositely charged ions.
43
What is the arrangement of ions in the lattice of an ionic compound?
The lattice has a regular arrangement of alternating positive and negative ions, held together by strong electrostatic forces of attraction.
44
What are the properties of ionic compounds?
Usually solid at room temperature and pressure (RTP). High melting and boiling points Conduct electricity in molten state or in solution Poor conductors in solid state
45
What are the properties of ionic compounds at room temperature and pressure (RTP)?
Ionic compounds are usually solid at RTP due to strong electrostatic forces between ions.
46
Why do ionic compounds conduct electricity in molten or solution states?
Ionic compounds conduct electricity when molten or in solution because the ions are free to move and carry charge.
46
How are covalent compounds formed?
Covalent compounds are formed when pairs of electrons are shared between atoms.
47
Why do ionic compounds have high melting and boiling points?
Ionic compounds have high melting and boiling points because a lot of energy is needed to break the strong electrostatic forces between the ions.
48
Why do ionic compounds not conduct electricity in solid state?
Ionic compounds do not conduct electricity in solid state because the ions are in fixed positions within the lattice and cannot move.
49
What is a covalent bond?
A covalent bond is a strong bond formed by the sharing of electron pairs between two atoms.
50
Which elements participate in covalent bonding?
Only non-metal elements participate in covalent bonding.
51
What are molecules?
When two or more atoms bond covalently, they are described as molecules.
52
What are Dot and Cross Diagrams used for?
Dot and Cross Diagrams are used to show the arrangement of electrons in covalent or ionic compounds, representing shared or transferred electrons between atoms.
53
What are the properties of simple molecular compounds?
Simple molecular compounds have low melting and boiling points, and they are usually liquids or gases at room temperature. As molecule size increases, melting and boiling points also increase.
54
Why do simple molecular compounds have low melting and boiling points?
Simple molecular compounds have low melting and boiling points because the forces between their molecules (intermolecular forces) are weak and require less energy to break.
55
Do simple molecular compounds conduct electricity?
No, simple molecular compounds are poor conductors of electricity because they don't have charged particles that are free to move.
56
Why do simple molecular compounds have low melting and boiling points?
Simple molecular compounds have low melting and boiling points because the intermolecular forces between the molecules are weak and require little energy to break.
57
How do intermolecular forces affect the state of small molecules?
The weak intermolecular forces in small molecules make them liquids or gases at room temperature, as these forces are not strong enough to hold the molecules in a solid form.
58
What happens to the melting and boiling points of simple molecular compounds as the molecule size increases?
As the size of the molecule increases, the intermolecular forces also increase, causing the melting and boiling points to rise.
59
Why are most simple molecular compounds poor conductors of electricity?
Most simple molecular compounds are poor conductors of electricity because they do not have free ions or charged particles to carry the charge in their solid or liquid states.
60
What are giant covalent structures?
Giant covalent structures are large networks of atoms bonded together by strong covalent bonds, forming a large, continuous structure, such as diamond or graphite.
61
What are the properties of diamond?
Diamond is a giant covalent structure where each carbon atom is bonded to four other carbon atoms in a tetrahedral arrangement. This makes diamond extremely hard, has a high melting point, and is a non-conductor of electricity due to the absence of free electrons.
62
Why is diamond so hard?
Diamond is hard because each carbon atom forms strong covalent bonds with four other carbon atoms, creating a rigid, 3D lattice structure that is difficult to break.
63
What are the properties of graphite?
Graphite is a giant covalent structure where each carbon atom is bonded to three others in flat layers. These layers can slide easily due to weak forces between them, making graphite slippery. It can conduct electricity due to free electrons between the layers.
64
Why is graphite a good conductor of electricity?
Graphite conducts electricity because each carbon atom has one delocalized electron that can move freely between layers, allowing electric current to pass through.
65
What makes graphite slippery?
Graphite is slippery because the layers of carbon atoms are held together by weak forces, so they can slide over each other easily.
66
What are allotropes of carbon?
Allotropes of carbon are different forms of the same element, where carbon atoms are arranged differently. This results in different physical properties. Examples include diamond, graphite, and graphene.
67
How do allotropes of carbon differ?
Allotropes of carbon differ in how their atoms are arranged and bonded. These differences in bonding lead to different physical properties such as hardness, conductivity, and density.
68
What are the main allotropes of carbon with giant covalent structures?
The main allotropes of carbon with giant covalent structures are diamond, graphite, and graphene. They differ in atom arrangement and bonding.
69
Why do allotropes of carbon have different physical properties?
The different properties come from how carbon atoms are arranged and bonded. For example, diamond is hard due to a rigid 3D structure, while graphite is soft and conductive due to its layered structure and free electrons.
70
How are carbon atoms arranged in a diamond?
In a diamond, each carbon atom forms strong covalent bonds with four others in a tetrahedral shape, creating a very strong 3D lattice.
71
What makes diamond so hard and strong?
Diamond’s hardness comes from each carbon forming four strong covalent bonds, resulting in a rigid and tightly packed 3D network.
72
How are carbon atoms arranged in graphite?
In graphite, each carbon atom bonds with three others in flat hexagonal layers, with one free electron per atom that moves between layers.
73
What is the structure of graphite like?
Graphite consists of flat hexagonal layers held together by weak intermolecular forces, allowing the layers to slide over each other easily.
74
Why can graphite conduct electricity?
Graphite conducts electricity because of the delocalized electrons that move freely between the layers.
75
What are the properties of diamonds?
Diamond is an insulator with no free electrons, has a high melting point, is hard and dense, and is used in jewelry and cutting tools.
76
Why is diamond an insulator?
Diamond does not conduct electricity because all electrons are used in covalent bonds and there are no free electrons to carry current.
77
What are the properties of graphite?
Graphite conducts electricity due to delocalized electrons, is slippery due to weak forces between layers, has a high melting point, and is less dense than diamond. It is used in pencils, lubricants, and electrodes.
78
Why is graphite a good electrical conductor?
It has free delocalized electrons that move through its structure and carry electric current.
79
Why is graphite smooth and slippery?
Because the layers of carbon atoms are held together by weak forces, they slide over each other easily.
80
What is silicon oxide (SiO₂)?
Silicon oxide is a macromolecular compound found in sand and quartz. Each silicon atom bonds with four oxygen atoms, and each oxygen bonds with two silicon atoms, forming a tetrahedral structure.
81
What are the properties of silicon oxide (SiO₂)?
SiO₂ is hard, has a high melting point, is insoluble in water, and does not conduct electricity due to no free electrons.
82
How does silicon oxide compare to diamond?
Both have strong covalent bonds and a tetrahedral structure. Like diamond, SiO₂ is hard and has a high melting point, but it's cheaper and does not conduct electricity.
83
What are the uses of silicon oxide (SiO₂)?
SiO₂ is used in sandpaper and to line furnaces. It's cheap and naturally available.

Chemistry (5 decks)

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