Unit Two: Covalent Bonding

Question 1

Covalent bonding:

Answer 1

Sharing electrons between two non metallic atoms

Question 2

What are giant covalent structures?

Name some features:

Answer 2

Macromolecules

They do not have charged ions
All the atoms are bonded to each other by strong covalent bonds
They have very high melting and boiling points
They don’t conduct electricity

Question 3

Name the three main examples of giant covalent structures:

Answer 3

Diamond-
Each carbon atom forms four covalent bonds in a very rigid giant covalent structure- makes it hard

Graphite-
Each carbon atom only creates three covalent bonds which creates layers which are free to slide over each other
Soft and slippery
Layers are held together loosely so can be rubbed off onto paper due to weak intermolecular forces

Silicon dioxide (silica)- 
What sand is made from 
Each grain of sand is one giant structure of silicon and oxygen

Question 4

What causes metal properties?

What are the properties of some metals?

Answer 4

The sea of fee electrons

Metals consists of a giant structure
Good conductors of heat and electricity
They allow layers of atoms to slide over each other, allowing metals to be bent and shaped

Question 5

What is an alloy and how is it formed?

Answer 5

A mix of two or more metals together which create the ideal properties that you want

Two or more metals are mixed together which distorts the layers of metal atoms, making it more difficult for them to slide over each other and also making them harder