Bonding Flashcards
(128 cards)
1
Q
Define ionic bond
A
The force of attraction between oppositely charged ions.
2
Q
Which electrons are involved in bonding?
A
Outer electrons.
3
Q
Elements form ions to achieve what?
A
The electronic structure of a noble gas.
4
Q
In a solid ionic compound oppositely charged ions attract and do what? how?
A
Form a lattice by electrostatic attraction.
5
Q
Ionic compounds, low or high m.p? why?
A
High, because lattice.
6
Q
What is a lattice?
A
A regularly repeating pattern of + and - ions.
7
Q
Formula for carbonate?
A
CO3^2-
8
Q
Formula for sulphate?
A
SO4^2-
9
Q
Formula for nitrate?
A
NO3^-
10
Q
Formula for nitrate?
A
NO3^-
11
Q
Formula for phosphate?
A
PO4^3-
12
Q
Formula for phosphate?
A
PO4^3-
13
Q
Formula for hydroxide?
A
OH^-
14
Q
Formula for ammonium?
A
NH4^-
15
Q
In a solid metal the metal is present as what?
A
Ions.
16
Q
What happens to the electrons the metal loses to becomes ions?
A
Become delocalised and form a sea around the regularly spaced ions.
17
Q
What holds the metal together?
A
The attraction between the delocalised e-s and the ions.
18
Q
What are two qualities of metals?
A
Malleable, conductors
19
Q
What is the force of attraction between ions and e-s?
A
Electrostatic.
20
Q
When does a giant ionic structure conduct?
A
In solution or molten.
21
Q
What arrangement to giant ionic structures have?
A
Regular crystal.
22
Q
Do covalent structures conduct electricity?
A
No.
23
Q
How are simple covalent structures arrangened?
A
Isolated molecules with WIF.
24
Q
Where are the strong bonds in covalent structures?
A
Between atoms.
25
High or low m.p for simple covalent?
Low, gases at room temp.
26
How are simple covalent structures arrangened?
Isolated molecules with WIF.
27
What arrangement do simple covalent have?
Regular crystal.
28
Giant covalent, high or low m.p?
High, solid at room temp.
28
Giant covalent, high or low m.p?
High, solid at room temp/
29
Do giant covalent conduct heat?
Yes.
30
What giant covalent conducts electricity?
Graphite.
31
What is a covalent bond?
A shared pair of electrons.
32
What do covalent bonds form between?
Non-metals.
33
What is a dative bond?
When one atom donates both e-s needed to bond.
34
What is needed for a dative bond?
One atom must have a lone pair and the other atom must have a vacant orbital for the pair.
35
Dative is also called?
Coordinate.
36
What are the five types of crystal types?
Monatomic, simple molecular, ionic, giant covalent and metallic.
37
Monatomic substances are all what at room temp?
Gases.
38
Ionic m.p and why?
High, lots of energy needed to break strong electrostatic attractions.
39
Ionic electrical conductivity and why?
Conducts when molten or dissolved in water, ions are free to move, water disrupts lattice and ions are free to move and carry the charge.
40
Ionic strength and why?
Hard but brittle, strong electrostatic forces between ions.
41
Ionic solubility and why?
Ions are free to move as water disrupts lattice.
42
Give an example of ionic.
Sodium chloride.
43
Simple molecular m.p and why?
Low, VDW forces between molecules are weak.
44
Simple molecular electrical conductivity and why?
No, electrons held in covalent bonds, no charged particles.
45
Simple molecular strength and why?
Soft and easy to break, VDW forces weak.
46
Simple molecular solubility and why?
Doesn't dissolve in water, only dissolves in non polar solvents.
47
Example of simple molecular?
Iodine, I2.
48
What does I2 do at room temp?
Sublime, solid into gas. Forms purple vapour when heated.
49
What forces can hold molecular substances together?
Van der Waals (VDW), dipole dipole, hydrogen bonding.
50
Ice is what crystal type?
Simple molecular.
51
Ice m.p and b.p and why?
M.p = 0C, b.p = 100C, hydrogen bonding raises expected temp, stronger intermolecular forces.
52
Ice electrical conductivity and why?
No, no charged particles.
53
Ice strength, why?
Breaks easily but hard, H bonding.
54
Diamond is an example of what?
Giant covalent.
55
In diamond C has what?
4 covalent bonds with 4 other C atoms.
56
What shape is diamond?
Tetrahedral.
57
M.p of diamond and why?
High, break strong covalent bonds.
58
Diamond electrical conductivity and why?
No, no free e-s.
59
Diamond solubility?
No.
60
Graphite is an example of what?
Giant covalent.
61
In graphite what does each C do?
Bond to 3 other C.
62
Graphite m.p and why?
High, lots of strong covalent bonds, lots of energy needed to break them.
63
Graphite electrical conductivity and why?
Yes, free e-s move through structure (plane of hexagons).
64
Graphite strength and why?
Soft, weak VDW hold structure together.
65
Graphite solubility?
No.
66
Strength of metallic bonding increases as?
Free e-s per atom increases, charge on + ion increases, size of + ion is smaller.
67
What makes metals shiny?
Free e-s cause metals to reflect light.
68
Metallic m.p and why?
High, + ions and free e-s held together by strong electrostatic forces.
69
Metallic electrical conductivity and why?
High, free e-s carry charge through structure.
70
Metallic strength and why?
Malleable and ductile, hammered into shape and drawn into wires, layers of ions slide over eachother.
71
Metallic solubility and why?
No, + ions and free e-s held together by strong electrostatic forces.
72
Define electronegativity.
The power of an atom to attract the pair of e-s in a covalent bond.
73
What elements have the highest electronegativity?
FONCl.
74
Define polarity.
The unequal sharing of e-s between atoms covalently bonded together.
75
What bond would be nonpolar and example?
2 atoms that are the same, eg. F2.
76
What bond would be polar and example?
2 atoms have different electronegativity. eg. HF.
77
What do we show using partial charges?
Which side of the molecule is more + or -.
78
What symbol do we use for partial charges?
δ+ and δ-.
79
Polar bonds have some what?
Ionic character.
80
Across a period, left to right, electronegativity does what?
Increases.
81
Up a group electronegativity does what?
Increases.
82
What are the factors that affect electronegativity?
Nuclear charge, atomic radius, shielding.
83
Explain nuclear charge.
More protons, stronger attraction from nucleus to bonding pair of e-s.
84
Explain atomic radius.
Closer the bonding pair of e-s to the nucleus the stronger the attraction between the two.
85
Explain shielding?
The less shells of e-s shielding and repelling the bonding e-s the stronger the attraction between the bonding pair of e-s and the nucleus.
86
Why does electronegativity decrease down a group?
Atomic radius gets larger, more shielding by e-s in inner shells, so less attraction between the nucleus and the bonding pair of e-s.
87
Why dies electronegativity across a period increase?
Nuclear charge increases, no. of inner e-s stay the same, atomic radius decreases, so stronger attraction between nucleus and bonding pair of e-s.
88
Low electronegativity indicates what bonding?
Covalent.
89
High electronegativity indicates what bonding?
Ionic.
90
In what molecules do VDW forces occur?
All.
91
In what molecules does dipole dipole forces occur?
Polar covalent bonds.
92
In what molecules does hydrogen bonding occur?
When H is bonded to NOF.
93
Which force is weakest?
VDW.
94
What force is strongest?
Hydrogen bonding.
95
How do VDW forces work?
e-s in a molecule are constantly moving and may be unequally distributed, causing a temporary dipole on the molecule.
96
When do VDW forces occur?
When a temporary dipole on one molecule induces a dipole on a neighbouring molecule.
97
VDW increases as?
Size of molecule increases, point of contact between molecules increases, straight chain hydrocarbons (weaker if branched), the shape of the molecule.
98
What will dipole dipole occur with?
With two molecules with permanent dipoles.
99
When does hydrogen bonding occur?
When H is bonded to NOF.
100
Why does hydrogen bonding occur?
Because H only has 2 e-s in the covalent bond, if they are pulled away from the atom the nucleus is exposed.
101
What is the 'H-bond' in hydrogen bonding?
The attraction between a lone pair on the NOF to the δ+ H on a neighbouring molecule.
102
What is the evidence for H bonding?
HF, H2O, and NH3 all have higher than average b.p.
103
In liquid water what do the h bonds do?
Break and reform easily as molecules move about.
104
When water freezes what happens to the H bonds.
Molecules are no longer free to move and H bonds hold the molecules in fixed positions.
105
What is the difference in the molecule density between water and ice?
Ice is slightly less closely packed.
106
Because ice is less dense than water where does it form?
On top of water.
107
Why is ice forming on top of water beneficial for life?
Insulates ponds during winter so fish can survive.
108
Where does hydrogen bonding also occur?
Alcohol, DNA.
109
What types of line do we use to represent bonding?
Normal line, wedge, dashed line.
110
What do the shapes of molecules and ions depend on?
Total no. of e- pairs around the central atom.
111
What are the two types of e- pairs?
Bonding and non bonding.
112
Define a bonding pair.
e-s in a covalent bond.
113
Define a non bonding pair.
Lone pairs.
114
What do e- pairs do to other e- pairs?
Repel as far as possible.
115
Which pairs repel further?
Lone pairs.
116
2 e- pairs and 2 bonding pairs makes what shape and angle?
Linear, 180 degrees.
117
3 e- pairs and 3 bonding pairs makes what shape and angle?
Trigonal planar, 120 degrees.
118
3 e- pairs and 2 bonding pairs makes what shape and angle?
Bent, 118 degrees.
119
4 e- pairs and 4 bonding pairs makes what shape and angle?
Tetrahedral, 109.5 degrees.
120
4 e- pairs and 3 bonding pairs makes what shape and angle?
Pyramidal, 107 degrees.
121
4 e- pairs and 2 bonding pairs makes what shape and angle?
Bent, 104.5 degrees.
122
5 e- pairs and 5 bonding pairs makes what shape and angle?
Trigonal bipyramidal, 120 and 90 degrees.
123
5 e- pairs and 4 bonding pairs makes what shape and angle?
Trigonal bipyramidal, 119 and 89 degrees.
124
5 e- pairs and 3 bonding pairs makes what shape and angle?
Trigonal planar or T-shape, 120 or 89 degrees.
125
6 e- pairs and 6 bonding pairs makes what shape and angle?
Octahedral, 90 degrees.
126
6 e- pairs and 5 bonding pairs makes what shape and angle?
Distorted square pyramid, 89 degrees.
127
6 e- pairs and 4 bonding pairs makes what shape and angle?
Square planar, 90 degrees.
