Giant Covalent Structures

Question 1

what are the 3 main giant covalent structures

Answer 1

1. diamond
2. graphite (and graphene)
3. silicon dioxide

Question 2

describe the bonding structure of diamond

Answer 2

Carbon forms 4 bonds giving it a full outer shell.
It has a tetrahedral structure
Joined by very strong covalent bonds

Question 3

describe (and explain) the properties of diamond

m.p/conductivity/texture

Answer 3

• High melting point - in order to melt a lot of energy is required to break the strong covalent bonds.
• Doesnt conduct because it has no ions or delocalised electrons to carry the charge
• Very hard because of the strong covalent bonds

Question 4

Give examples of the uses of diamond

Answer 4

Drill bits, jewellery

Question 5

describe the bonding structure of graphite

Answer 5

• The carbon atoms for 3 bonds and have one delocalised electron.
• It is made up of layers of graphene
• Trigonal planar structure

graphene is a layer of hexagons made up of carbon

Question 6

describe and explain the properties of graphite

Answer 6

• High melting point - in order to melt a lot of energy is required to break the strong covalent bonds.
• Does conduct electricity due to the delocalised electrons that can move through the structure and carry the charge.
• soft - the layers of graphene slide over each other easily and are only held together by weak London forces

Question 7

give examples of uses of graphite

Answer 7

pencils, machine lubricant, electronics

Question 8

describe the bonding structure of silicon dioxide

Answer 8

• ## similar to diamond except between each pair of silicon atoms there is an oxygen atom

Joined by very strong covalent bonds

It has a tetrahedral structure

Question 9

describe and explain the properties of silicon dioxide

Answer 9

• High melting point - in order to melt a lot of energy is required to break the strong covalent bonds.
• Doesnt conduct becuase all of its atoms are fixed in bonds and cannot move
• Hard - entire structure is make from strong covalent bonds

Question 10

give examples of uses of silicon dioxide

Answer 10

glass making

Question 11

How is graphene similar to copper

Answer 11

They both have the same electrical conductivity

Question 12

What is unique about graphene

Answer 12

It is the strongest and thinest material ever made