P1: 3 Bonding

Question 1

What does ionic bonding involve?

Answer 1

Strong electrostatic attraction between oppositely charged ions in a lattice.

Question 2

What does a single covalent bond contain?

Answer 2

A shared pair of electrons.

Question 3

What do multiple covalent bonds contain?

Answer 3

Multiple shared pairs of electrons.

Question 4

What does a co-ordinate (dative covalent) bond contain?

Answer 4

A shared pair of electrons with both electrons supplied by one atom.

Question 5

What does metallic bonding involve?

Answer 5

Attraction between delocalised electrons and positive ions arranged in a lattice.

Question 6

What are the four types of crystal structure?

Answer 6

Ionic.
Metallic.
Macromolecular (giant covalent).
Molecular.

Question 7

What are bonding and lone pairs of electrons?

Answer 7

Charge clouds that repel each other.

Question 8

What do pairs of electrons in the outer shell do?

Answer 8

Arrange themselves as far apart as possible to minimise repulsion.

Question 9

What type of repulsion is greater in pairs of electrons?

Answer 9

Lone pair - lone pair. (greatest)
Lone pair - bond pair.
Bond pair - bond pair (weakest)

Question 10

What is electronegativity?

Answer 10

The power of an atom to attract the pair of electrons in a covalent bond.

Question 11

What produces a polar covalent bond?

Answer 11

The electron distribution in a covalent bond between elements with different electronegativities will be asymmetrical.

Question 12

What shape and bond angle does 2 bonding pairs and 0 lone pairs make?

Answer 12

Linear, 180

Question 13

What shape and bond angle does 3 bonding pairs and 0 lone pairs make?

Answer 13

Trigonal planar, 120

Question 14

What shape and bond angle does 2 bonding pairs and 1 lone pair make?

Answer 14

Bent (V-shape), 118

Question 15

What shape and bond angle does 4 bonding pairs and 0 lone pairs make?

Answer 15

Tetrahedral, 109.5

Question 16

What shape and bond angle does 3 bonding pairs and 1 lone pair make?

Answer 16

Trigonal pyramidal, 107

Question 17

What shape and bond angle does 2 bonding pairs and 2 lone pairs make?

Answer 17

Bent V-shape, 104.5

Question 18

What shape and bond angle does 5 bonding pairs and 0 lone pairs make?

Answer 18

Trigonal bipyramidal, 120 and 90

Question 19

What shape and bond angle does 4 bonding pairs and 1 lone pair make?

Answer 19

Trigonal pyramidal, 119 and 89
Or
See-saw, 119, 89

Question 20

What shapes and bond angles does 3 bonding pairs and 2 lone pairs make?

Answer 20

Trigonal planar, 120
Or
T-shape, 89

Question 21

What shape and bond angle does 6 bonding pairs and 0 lone pairs make?

Answer 21

Octahedral, 90

Question 22

What shape and bond angle does 5 bonding pairs and 1 lone pair make?

Answer 22

Square pyramid, 89

Question 23

What shape and bond angle does 4 bonding pairs and 2 lone pairs make?

Answer 23

Square planar, 90

Question 24

What are the rules for working out the shape of molecules and ions?

Answer 24

1. How many electrons are around the central atom?
2. Add 1 electron for each bond.
3. Add 1 electron for a negative charge, deduct 1 electron for a positive charge.
4. Divide total by 2 to give number of pairs.
5. How many bonding pairs and lone pairs?
6. Arrange electrons in space to minimise repulsion.
7. Treat double bonds as a single unit.

Question 25

What is the formula of the compound ion sulfate?

Answer 25

SO4 2-

Question 26

What is the formula of the compound ion hydroxide?

Answer 26

OH -

Question 27

What is the formula for the compound ion nitrate?

Answer 27

NO3 -

Question 28

What is the formula for the compound ion carbonate?

Answer 28

CO3 2-

Question 29

What is the formula for the compound ion ammonium?

Answer 29

NH4 +

Question 30

What are the melting and boiling points of molecular substances influenced by?

Answer 30

The strength of the intermolecular forces.

Question 31

What are the intermolecular forces in order of strength?

Answer 31

Van der Waals Permanent dipole-dipole forces Hydrogen bonding

Question 32

Where are van der Waal’s forces present?

Answer 32

In all molecular substances.

Question 33

Why do van der Waal’s forces occur?

Answer 33

Electrons are constantly moving around so there will always be an uneven electron distribution (partly due to electronegativity). This causes a temporary dipole within a molecule. This induces a temporary dipole in a neighbouring molecule. There is an attraction between these molecules - temporary induced dipole-dipole attraction.

Question 34

What affects the power of van der Waal’s forces?

Answer 34

The bigger the molecule, the greater the van der Waal’s forces.

Question 35

Where does permanent dipole-dipole attraction occur?

Answer 35

Between polar molecules.

Question 36

Where does hydrogen bonding occur?

Answer 36

Where an H atom is bonded to a very electronegative atom. Only fluorine, oxygen and nitrogen.

Question 37

How does a hydrogen bond occur?

Answer 37

The polar bond between the H and F/O/N atom leaves the H nucleus exposed. Therefore, there is a strong attraction from the lone pair on the F/O/N of one molecule to the exposed H nucleus of another molecule. This is the strongest intermolecular force.

Question 38

What are the properties of substances with ionic bonding?

Answer 38

High melting/ boiling points. Typically solid at rtp. Doesn’t conduct electricity except when liquid. Soluble in water.

Question 39

What are the properties of substances with molecular bonding?

Answer 39

(Simple covalent) Low melting and boiling points. Typically solid at rtp (except for I2 which is solid). Doesn’t conduct electricity. Solubility depends on how polarised the molecule is.

Question 40

What are the properties of substances with macromolecular bonding?

Answer 40

High melting and boiling points. Typically solid at rtp. Doesn’t conduct electricity (except graphite) Sublimes rather than melts. Not soluble in water.

Question 41

What are the properties of substances with metallic bonding?

Answer 41

High melting/ boiling points. Typically solid at rtp. Does conduct electricity. Not soluble in water.

Question 42

What is the structure of diamond?

Answer 42

A macromolecular allotrope of carbon. There is covalent bonding between every carbon atom.

Question 43

What is the structure of graphite?

Answer 43

A macromolecular allotrope of carbon. Has strong covalent bonds between carbon atoms but weak van der Waals forces between layers.

Question 44

What is the structure of iodine?

Answer 44

A molecular crystal. There is a strong covalent bond that holds two iodine molecules together. Since iodine molecules have a large number of electrons, the van der Waals forces are strong enough to hold the molecules together as a solid. But van der Waals are much weaker than covalent bonds.

Question 45

Why do some molecules with polar bonds not have a permanent dipole?

Answer 45

Overall, the molecule isn't polar.

Question 46

What is the structure of sodium chloride?

Answer 46

Giant ionic lattice.

Question 47

What is the structure of magnesium?

Answer 47

Giant metallic lattice.

Question 48

What is the structure of ice?

Answer 48

Lattice. Less dense than water.