11:Structure and Bonding

Question 1

What is metallic bonding

Answer 1

The attraction between a lattice of positive ions and a sea of delocalised electrons.

Question 2

Why are metals good conductors of electricity

Answer 2

Because the delocalised electrons are mobile

Question 3

Physical properties of metals

Answer 3

Conduct heat and electricity,
High melting points (with exceptions eg. mercury)
Malleable
Ductile
Shiny
Sonorous (make a sound when struck)

Question 4

What are simple molecular structures

Answer 4

Each molecule is made up of a defined number of atoms, covalently bonded together. These molecules are then attracted together by intermolecular forces.

Question 5

General properties of simple molecular structures

Answer 5

Relatively low M.P. and B.P.
Low electrical conductivity
Low solubility in water

Question 6

What are giant covalent lattice structures

Answer 6

A giant covalent structure is one in which the covalent bonding extends throughout the whole crystal, usually in three dimensions (but occasionally, as in graphite, only in two).

Question 7

Examples of giant covalent lattice structures

Answer 7

Diamond
Silicon
Graphite
Graphene

Question 8

Properties of diamond

Answer 8

Very high melting point (over 4000ºC)

Very hard

Non conductor

Question 9

Why does graphite conduct electricity

Answer 9

Carbon is bonded to 3 other carbons so the fourth electron in C’s outer shell is delocalised and conducts.

Question 10

Properties of graphite

Answer 10

Slippery as it is layers held together by weak forces so they can slide over each other
Very high melting point
Conducts electricity

Question 11

Properties of graphene

Answer 11

Extraordinarily high tensile strength

Very high electrical conductivity