Types of Bonding

Between 2 non-metals

Formation

Share electrons to get a full outer shell

• One shared pair - single bond
• Two shared pairs = double bond (oxygen)

Properties

Simple covalent substances have:

• low boiling points (turn to gas easily)
• weak intermoleular forces between molecules
• so little energy is need to overcome these forces

Between a metal and a non-metal

Formation

Metal lose outer electrons to get a full outer shell - become positively charged

Non-metals gain electrons to get a full outer shell - become negatively charged

Properties

Ionic substances have:

• high melting points - so are solids
• large lattice structure
• strong electrostatic forces between oppositely charged ions
• can conduct electricity (in molten or solution form) - because ions can move freelyto electrodes

Between metals

Formation

Bond held together by the strong electrostatic forces between the postive nucleus and the negative sea of delocalised electrons

Properties

Pure metals are:

• soft - same size atoms
• arranged in layers - can slide over each other

Alloys are:

• hard - different size atoms
• layer are distorted  - cannnot slide

Metals can conduct electricity - sea of delocalised electrons that can flow between layers.

Graphite, diamond and silicon dioxide

Formation

Graphite - 3 carbon bonds

Diamond - 4 carbon bonds

Properties

Graphite is:

• soft (good lubricant) - arranged in layers 
• weak intermolecular forces between the layers - layers can slide
• conducts electricity - free electrons flow between the structure carrying charge

Diamond is:

• hard - 4 carbon bonds in a rigid lattie structure
• with stong covalent bonds
• no layers to slide