C3.7 Giant Covalent Structures

Question 1

What are Two Forms of the Element Carbon?

Answer 1

Diamond and Graphite

Question 2

What are the general properties of substances with giant covalent structures?

Answer 2

-Some covalently bonded structures have giant structures
-Very high melting and boiling points.
(Diamond = 4827°C)

Question 3

Why is diamond hard but graphite is slippery?

Answer 3

• Graphite has giant layers of covalently bonded carbon atoms,but there are no covalent bonds between the layers.
• Meaning they can slide over each other,making graphite soft and slippery.
• Diamond is hard because the carbon atoms have a rigid giant covalent structure,making it a hard substance.

Question 4

Why can graphite conduct electricity and thermal energy?

Answer 4

-Because of the deliocalised electrons that can move along its layers.

Question 5

What compound has a similar structure to diamond?

Answer 5

Silicon Dioxide,SiO(2)

Question 6

How do delocalised electrons conduct electricity within giant covalent structures?

Answer 6

-Because the electrons will drift away from the negative terminal of a battery and towards and positive terminal when put into an electrical circuit.

Question 7

Why can’t diamond conduct electricity?

Answer 7

-Diamond,and most other covalently bonded strucutres,cannot conduct electricity.
This is because the atoms don’t have free electrons as the outer shell is involved in covalent bonding.