c2.3

Question 1

why can carbon form so many compounds

Answer 1

ability to form 4 covalent bonds

Question 2

allotropes

Answer 2

different forms of an element in the same state but with different atomic arrangements.
eg, diamond and graphite are allotropes of carbon

Question 3

diamond

Answer 3

giant covalent structure
each carbon atom covalently bonded to four other carbon atoms
many strong covalent bonds - high melting point and very hard
no delocalised electrons - not good conductors

Question 4

graphite

Answer 4

giant covalent structure
each carbon atom covelently bonded to three other carbon atoms - one electron in outer shell of each electron is not bonded
this electron becomes delocalised - graphite conducts electricity even though it is non-metal
layered structure
strong covalent bonds - high melting point
weak intermolecular forces between layers - layers can slide over each other easily - why graphite is slippery

Question 5

graphene

Answer 5

carbon allotrope
single layer of graphite
almost transparent, extremely strong and conducts electricity.

Question 6

bonds involved in state changes
metal
ionic compound
simple molecule
giant covalent structure

Answer 6

metallic bonds
ionic bonds
intermolecular forces
covalent bonds

Question 7

why are metals malleable

Answer 7

metal ions held in lattice + strong intermolecular forces due to metallic bonds
when large enough external force applied, layers slide over each other but as delocalised electrons are free to move no bonds are broken

Question 8

nanoparticles

Answer 8

large surface area to volume ratio
very small, can be absorbed by skin or breathed in - take a long time to break down and toxic substances may stick to their surfaces - harmful