Covalent Structures Flashcards
What groups form simple molecular structures?
Groups 15, 16 and 17
What bonds and forces do simple molecular molecules have
Covalent bonds
(Weak) London forces
Why are simple molecular substances poor conductors?
Their structure contains no charged particles.
What type of covalent structure is diamond?
Macromolecular / giant covalent
What is the structure diamond atoms are covalently bonded into?
A giant lattice structure
How many bonds does each atom in a graphite structure form?
4
Why is the melting point of diamond high?
Each carbon atom forms 4 covalent bonds, which are very strong
Why are macromolecular substances like diamond rigid?
Had a very strong covalent lattice
What is diamond’s relative hardness and strength?
Very hard
Very strong
What type of covalent structure is graphite?
Macromolecular / giant covalent
How many bonds does each carbon atom form?
Forms 3 covalent bonds
What is graphite made up of?
Flat sheets of graphene
Why can graphite conduct electricity?
The electrons not used in bonding are released as free electrons which move between layers.
Within each layer, what is the relative strength of the covalent bonds?
They are very strong
What forces occur between each layer and what is their strength?
London forces which are very weak
Why is graphite a good lubricant?
Weak london forces between layers allow them to slide over each other easily
What dimensions does graphene have?
2D
What is the thickness of graphene?
One atom thick
What are the graphene sheets formed of?
Hexagonal carbon rings
What are 3 important properties of graphene?
- very strong
- rigid
- extremely lightweight
Can graphene conduct electricity?
Yes - delocalised electrons move through each layer
