Chemistry: Module 1 Flashcards
(102 cards)
1
Q
Periodicity
A
periodicity refers to trends or recurring variations in the properties of elements in the periodic table of elements
2
Q
Hydroxide (polyatomic ion)
A
OH-
3
Q
Sulfate (polyatomic ion)
A
SO₄²⁻
4
Q
Sulfite (polyatomic ion)
A
SO₃²⁻
5
Q
Carbonate (polyatomic ion)
A
CO₃²⁻
6
Q
Ammonium (polyatomic ion)
A
NH₄⁺
7
Q
Phosphate (polyatomic ion)
A
PO₄³⁻
8
Q
Nitrate (polyatomic ion)
A
NO₃⁻
9
Q
Nitrite (polyatomic Ion)
A
NO₂⁻
10
Q
Ion
A
a charged particle that forms during chemical changes when one or more valence electrons transfers from one atom to another
11
Q
Ionic bond
A
a bond between metals and nonmetals that bond because one loses electrons and the other gains electrons due to the tendency to FILL VALENCE SHELLS
12
Q
Cation
A
Positive ions (elections are lost) ~ usually metals
13
Q
Anion
A
Negative ions (elections are gained) ~ usually non-metals
14
Q
Electrostatic Attraction
A
The intramolecular force between positively charged particles (e.g. cations) and negatively charged particles (e.g. anions).
Electrostatic attraction exists in structures such as metallic and ionic lattices in which metal cations are electrostatically attracted to anions or a sea of delocalized electrons respectively.
15
Q
Electronegativity
A
The energy required for an atom to attract/draw in electron density/electrons with the purpose of filling a valence shell.
16
Q
Ionisation Energy
A
The energy required in order to remove an electron from an atom or ion’s valence shell (in order to fill valence shells)
17
Q
Lattice Structure
A
A strong (rigid in ionic, malleable in metallic) 3D structure whereby positively charged particles are dispersed with negatively charged particles, held together by a strong intramolecular force: electrostatic attraction.
18
Q
Simple Covalent Molecular Structure
A
A simple covalent bond between two or more non-metals to form a molecule. Eg. H₂O & C₂O.
19
Q
Intermolecular Forces
A
Forces between independent, identical or unlike molecules in a substance.
20
Q
Describe the trends in electronegativity down groups and across periods in the periodic table.
A
Electronegativity:
- Ascends (increases) Across a period →
as the nuclear force gets stronger, pulling
electron density closer to the nucleus of the atom - Decreases Down a group →
as electron shielding increases, reducing the
effect of the nuclear charge on attracting more
electrons.
21
Q
Describe the trends in ionisation energy within groups and across periods in the periodic table.
A
Ionization energy (inverse of electronegativity):
- Increases across a period →
as nuclear charge gets stronger upon receiving
more protons whilst keeping the same amount of
electron shielding, it is harder for valence shells
to lose electrons - Decreases down a group →
as more electron shielding is added due to the
increase in electron orbitals, the effect of the
nuclear charge is weakened and is thus easier to
lose electrons in the valence shell.
22
Q
Giant Covalent Network Structure
A
A complex system of strong covalent intramolecular bonds that bind non-metals together.
23
Q
What type of bond is diamond? Can it be limitless?
A
Diamond is an allotrope and is a giant covalent network. The diamond allotrope can be limitless with a range of different sizes of a diamond.
24
Q
Does diamond conduct electricity? Explain why or why not?
A
Diamond cannot conduct electricity because each carbon atom (in an unlimited structure) is bonded to 4 other carbon atoms in a tetrahedral arrangement, there are NO FREE ELECTRONS to allow for a current to pass through.
25
Does the diamond have a high melting and boiling point? Explain why or why not?
Diamond has very high melting and boiling point as a great deal of heat energy is required to overcome the strong covalent bonds.
26
Is diamond-hard or soft? Explain why.
Diamond is incredibly hard and brittle as there are strong and stiff covalent bonds holding the covalent network structure together.
27
What type of bond is graphite? Is it limitless?
Graphite is a giant covalent network structure which is also an allotrope of carbon. It can have an unlimeted amount of graphene laters and can therefore, theoretically, be limitless in structure.
28
Does graphite conduct electricity? Explain why or why not?
Graphite does indeed conduct electricity, however, only in a horizontal direction.
29
Does graphite have a high melting and boiling point? Explain why or why not?
Graphite has a high melting and boiling point as there are strong intramolecular covalent bonds that require great amounts of heat energy to overcome.
30
Is graphite hard or soft? Explain why.
Graphite is soft due to the weak intermolecular forces between each graphene sheet. It can act as a lubricant as the electrons allow for each sheet to slide over each other. However, it is not malleable.
31
Is graphite malleable or brittle?
Brittle
32
What type of bond is buckminster fullerene? Is it limitless.
Covalent network structure that exist as seperate molecules and are thus, not limitless networks.
33
Does buckminster fullerene conduct electricity? Explain why or why not?
Fullerene is a poor conductor of electricity as each carbon atom is bonded with only 3 other carbon atoms, meaning that there are freely moving delocalized electrons. However, as these electrons are contained within the boundaries of a fullerene molecule, there isn't an effective pathway for current to travel through the structure.
34
Does buckminsterfullerene have a high melting and boiling point? Explain why or why not?
Fullerene has high melting and boiling points due to the strong intramolecular covalent bonds requiring great heat energy to overcome them.
35
Is buckminster fullerene hard or soft? Explain why.
Fullerene is hard due to the strong covalent bonds holding the carbon atoms together.
36
Is diamond malleable or brittle? Explain why.
Diamond is brittle and will shatter. This is due to the strong intramolecular covalent bonds.
37
Define "Allotropy" and provide an example
Allotropy is the ability for an element to adopt two or more physical forms. These different physical forms (all comprised of the same type of element) are called allotropes.
Some allotropes include:
- Carbon: graphene, graphite, diamond, fullerene
- Oxygen: oxygen, ozone
- Phosphorus: yellow phosphorus, black phosphorus, red phosphorus.
38
Are allotropes exclusively composed of carbon atoms?
No, there can be oxygen, phosphorus, and a range of other types of elemental allotropes.
39
Describe the properties of ionic structures
As solid, Ionic structures take form as a strong 3D lattice structure: due to the strong electrostatic attraction between the positively charged cations and the negatively charged anions.
Can't conduct electricity in solid lattice state: as all anions are bonded to cations, not allowing for a flow of current.
They can only conduct electricity when in molten (l) or aqueous (aq) state: as there are freely moving ions which can conduct electricity.
High melting and boiling points: due to the strong electrostatic attraction between oppositely charged ions which requires great heat energy to overcome and break.
Brittle: as ions can shift and repel against each other when pressure/force is applied to it.
40
Describe the properties of metallic structures
Strong (electrostatic attraction) 3D lattice structure
Good conductor of electricity: as there is a sea of delocalised and freely moving electrons which allows for the flow of current.
Malleable: as the structure is not rigid and as there are delocalised electrons when force is applied to the lattice structure, electrons can move and maintain their electrostatic attraction to cations; preventing repulsion.
Lustrous: as light can reflect off the sea of electrons.
High melting and boiling points: due to the strong electrostatic attraction between cations and electrons requiring great heat energy to overcome.
41
What are covalent bonds and why do they form?
Covalent bonds are those between two non-metals that SHARE one or more PAIR(S) of electrons in order to fill their valence shells.
42
Write the chemical equation for the following ionic bonds:
- Sodium Chloride
- Aluminum Oxide
- Calcium Sulphate
- Phosphorus Carbonate
- Lithium Phosphate
- Boron Nitrate
- Ammonium Chloride
- NaCl
- Al₂O₃
- CaSO₄
- Covalent Bond (both anions)
- Li₃P
- B(NO₃)₃
- NH₄Cl
43
What is a Lewis diagram?
A Lewis diagram displays a covalent bond with bonding pairs represented as bars. A single bar represents a single pair, double bars represent a double bond, etc.
The remaining electrons are represented by closed circles.
44
Write the chemical equation for the following covalent bonds:
Sulfur trioxide
Triphosphorus Pentachloride
Nitrous gas
Fluorine gas
Neon gas
- SO₃
- P₃Cl₅
- N₂O
- F₂
- Ne
45
What is a polar molecule?
A molecule with unevenly distributed charges ie. different parts of the molecule have electronegativity differences.
46
When and why can ionic compounds conduct electricity?
In a molten or aqueous (dissolved) state as electricity can flow through freely moving IONS (not electrons).
47
What elements exist monotonically?
All noble gases (group 8) have a full valence shell and don't want to bond with any other atom.
48
What elements exist diatomically?
All elements ending in 'gen' and the halogens:
- Hydrogen
- Nitrogen
- Oxygen
- Halogens
49
Define molecule
A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
50
Are ionic structures molecules? Why or why not? Provide an example.
No. They are a fixed ratio of ionically bonded elements. Ionic structures usually exist (in a solid-state) in a giant 3D lattice structure with millions of ions within them and are therefore not molecules. For example, sodium chloride (NaCl) is just a 1:1 ratio that describes for every sodium atom, there will be one chloride atom. However, the giant 3D lattice is complex with innumerable amounts of these ions in one grain of table salt and therefore is not a molecule.
51
What is a polyatomic ion?
A polyatomic ion is a molecule, that has been formed through covalent bonding, with an overall (net) charge and is thus an ion.
52
What is a nonpolar covalent bond?
A type of bond that results in the equal sharing of electrons (the same electronegativity of both atoms).
53
Is carbon dioxide a polar or nonpolar covalent molecule?
Carbon dioxide is nonpolar as it is asymmetrical covalent bond.
54
What are metal alloys?
Metal alloys are combinations of different types of elements with one or more types of metals that can produce the most optimal properties.
55
What holds covalent bonds together?
The electrostatic force of attraction between the positively charged nuclei and the shared pair(s) bonding electrons are negatively charged.
56
Lone Pair
A pair of electrons that do not bond on the central atom.
57
Bonding Pair
A shared pair of electrons in a covalent bond.
58
Electron Domain
The space occupied by a set of bonded electrons or lone pairs. It is simply the sum of the no. of bonding pairs and the no. of lone pairs.
59
A molecule is symmetrical when?
The electron domain = the no. of bonding pairs i.e. no lone pairs on the CENTRAL atom.
60
Tetrahedral Shape
Tetrahedral
- 4 bonding pairs
- 0 lone pairs
- 4 electron domains (DOT AND WEDGE)
- angle between each atom is 109.5°
61
Trigonal Planar
Trigonal Planar
- 3 bonding pairs
- 0 lone pairs
- 3 electron domains
- angle between each atom is 120°
62
Trigonal Pyramidal
Trigonal pyramid(al)
- 3 bonding pairs
- 1 lone pair
- 4 electron domains (DOT AND WEDGE)
- angle between each atom is 107°
63
V-shape/bent
V-shape / bent
- 2 bonding pairs
- 1 or 2 lone pairs
- 3 or 4 electron domains
- angle between each atom is 105°
64
Linear
Linear
- 2 bonding pairs
- 0 lone pairs
- 2 electron domains
- angle between each atom is 180°
65
What is the polarity of a molecule dependant on?
Size, shape, and the polarity of covalent bonds (dipoles).
66
Are diatomic molecules polar or nonpolar?
Diatomic molecules are nonpolar as they have equal electronegativity charges and they are symmetrical.
67
The VSEPR Theory
(Valence Shell Electron Pair Repulsion) The theory that the negatively charged electrons in bonds and lone pairs repel one another leading to the formation of specific molecular geometries.
68
Different types of intermolecular forces
Dispersion forces (present in all molecules)
∙ Permanent Dipole-Dipole Interactions (in polar molecules)
∙ Hydrogen Bonds (in polar bonds with hydrogen and lone pairs on fluorine, oxygen, or nitrogen)
69
Dispersion Forces
An intermolecular attraction between 2 polar or non-polar molecules caused by the temporary dipoles created by the constant movement of electrons. They are the weakest type of intermolecular attraction
70
Dipole-Dipole Force
The slightly charged positive end of one dipole electrostatically attracts to the slightly negative end of the other dipole thus forming a permanent dipole-dipole interaction.
71
Hydrogen Bonds
Strong dipole-dipole attractions (50x stronger than dispersion forces) occur between partially positive hydrogen atoms (electron-deficient) and the partially negative nitrogen, oxygen, or fluorine atoms (due to lone pairs).
72
Are Ionic lattice structures compounds?
They are compounds cause there are bloody millions of ionic bonds within a lattice structure.
73
Atomic No. (Z)
The number of protons there are in a nuclues and therefore, the number of electrons there are *IN A NEUTRAL ATOM*
74
Electron Arrangement
A diagram displaying the electron patterns in an atom or group of bonded atoms such as dot and cross ionic diagrams.
75
What neutral atom is represented by the electron configuration:
1s2 2s2 2p4?
Oxygen
76
What does the principal quantum number indicate?
The energy level of an orbital.
77
What is an orbital?
An orbital is a path that 2 max. electrons may follow around a nucleus
78
What is a sub-shell?
A sub-shell is an electron shell comprised of (one or multiple) orbital/s.
79
How many orbitals are found in the d sub-shell?
5
80
How many orbitals are found in the p sub-shell?
3
81
How many orbitals are found in the s sub-shell?
1
82
How many orbitals are found in the f sub-shell?
7
83
What are the different subshells?
s,p,d,f
84
In a flame test, what colour does Sodium Chloride turn?
Yellow
85
What causes a change in colour in a flame test?
As the metal ion absorbs photons from the flames, they get excited and increase their energy. This allows them to ascend sub-shells through a process of excitation. Then, the emitt photons in a proccess of de-excitation in which the decrease in energy produce a unique light wavength in the emission light spectra. This forms an observable colour change.
86
What is a photon?
A photon is a "packet of light" or, electromagnetic radiation.
87
In any orbital, what can be said about the two electrons?
They have opposite spin.
88
What is an isotope?
Different variations of elements accounted for by different numbers of neutrons in the nucleus of an atom.
89
What is an ion?
A charged particle formed when an atom, or group of atoms, loses/gains electrons to form cations or anions respectively in order to fill their valence shell.
90
What is the Relative Molecular Mass?
Relative molecular mass is the average mass of a molecule rather than an atom.
91
What is the relative formula mass?
The sum of the relative atomic masses of each atom in the repeating unit of the structure.
92
First ionisation energy
The required amount of energy (kj/mol) needed for the removal of an electron from each atom in a mole of gaseous atoms.
93
Properties of compounds
```
Conductivity
Melting and boiling points
Hard
Brittle
Lustrous
```
94
Miscible liquids
Mixtures whose liquids mix evenly with each other (leaving no visible layers) such as a solution of acetic acid (vinegar solution).
95
Immiscible liquids
Mixtures whose liquids do not mix evenly with each other (leaving visible layers) such as suspension mixture of oil atop water.
Mixtures whose liquids do not mix evenly with each other (leaving visible layers) such as suspension mixture of oil atop water.
96
Ion
a charged atom with an unequal number of protons and electrons (through losing or gaining electrons)
97
What is an Element?
An element is a substance that is made from only one type of atom (identical atoms). There are 114 known elements that make up the universe and are found on the Periodic Table.
98
What are the two types of pure substances?
Elements and Compounds
99
What is a compound?
A compound is a substance that is made of atoms of different elements (unique atoms) that are chemically bonded together.
100
What is a molecule?
A molecule is a group of atoms that are chemically bonded together that represents the smallest and simplest unit of a chemical compound.
101
Matter
Has mass, takes up space and exhibits inertia.
Matter can be separated into two categories, pure substances and mixtures.
102
What are pure substances?
Pure substances have definite compositions, are made up of only one type of particle and can be an element or compound (i.e. hydrogen gas or water).
