2.4 EXT Structure and Bonding

Question 1

Structure of metal solid

Answer 1

Metals are made up of a 3D lattice with strong non-directional electrostatic attractions between the positively charged metal nuclei and the sea of delocalised valence electrons called metallic bonding.

Question 2

Ionic solid sturcture

Answer 2

Ionic substances are made up of a 3D lattice with alternating positive and negative ions held together with strong directional ionic bonds. The ions are fixed in place.

Question 3

Molecular solid structure

Answer 3

Molecular substances are made up of discrete molecules held together with weak intermolecular forces. These molecules are not charged.

Question 4

Covalent Network Structure- Diamond

Answer 4

Each carbon atom is covalently bonded to 4 other carbon atoms forming a strong 3-D covalent network lattice with no free electrons.

Question 5

Covalent Network Structure- Silica

Answer 5

Each silicon atom is covalently bonded to 4 oxygen atoms and each oxygen atom is covalently bonded to two silicon atoms in a 3-D covalent network lattice with no free electrons.

Question 6

Covalent Network Structure- Graphite

Answer 6

Each C atom in graphite is covalently bonded to 3 other carbon atoms resulting in hexagonal rings which are arranged in layers. Each C atom, therefore, has a delocalised valence electron. There are weak inter-layer bonds formed between the delocalised electrons of two consecutive layers.

Question 7

Explain why Hydrogen Cynide is Polar while Carbon Dioxide is Non-Polar
Molecule (LS):
Polarity Of molecule:

Question 8

Explain why CCL4 and CH3Cl have different polarity
Molecule (LS):
Polarity of Molecule:

Question 9

Carbon (Graphite), conducts electricity as a solid, whereas ZnCl2, deos not conduct electricity when solid, but will conduct electricity when in a molten state. Justify the statements in terms of particles, structure, and bonding for substance.

Question 10

Sodium is malleable, whereas NaI is brittle and will shatter when a force is applied upon it. Justify the statements in terms of particles, structure, and bonding for substance.

Question 11

At the Bluff aluminium smelter, aluminium is produced by passing an electirc current through molten aluminium oxide. The product, sluminium, will conduct an electric current when it is solid.
Discuss the eletrical conductivity of aluminium oxide and alumininum in solid and liquid form. In your discussion you should make references to:
- the structure of the solids
- the particles carrying the current

Question 12

Draw and label a diagram for an exothermic reaction

Question 13

Draw and label a diagram for and endothermic reaction