Chemistry: Different types of bonding / structure

Current is the flow of charged particles

Ionic Bonding

• Positive ions are attracted to negative ions - this is called electrostatic attraction

• Ionic bonding is between a metal and a non-metal. It is the transfer of electrons

• Arranged in a lattice structure

• Very strong electromagnetic forces causing high melting / boiling points as requires more energy to break bonds

• Ions are very tightly held together causing high melting / boiling points

• Cannot conduct electricity when solid as there are no delocalised (free) electrons

• Can conduct electricity when melted

• Can conduct electricity when dissolved in water

Simple Covalent Molecules (SCB)

• Simple covalent is between non-metals and is the sharing of electrons

• Low boiling points - weak intermolecular forces, which require little energy to break

• Cannot conduct as there are no delocalised electrons

Giant Covalent structures

• Only: diamond, graphite, graphene, silicon dioxide, fullerenes and nano-tubes

• Diamond, Silicon dioxide and fullerenes: can’t conduct electricity as they don’t have delocalised electrons - each carbon has 4 bonds

• While Graphite and Graphene: can conduct electricity as there’s delocalised electrons- each carbon has 3 bonds

• All: have a high melting point as they all have strong covalent bonds that require a lot of energy to break

• Diamond and Silicon dioxide: are very strong because of a tetrahedron shape

• Graphite: is used as a lubricant because the layers can slide over each other

• Fullerenes: are used as a lubricant because they are ball shaped - they can roll

Metallic Bonding

• Metals have giant structures

• The positive ions are arranged in regular layers

• The outer electrons from each metal atom becomes delocalised and can easily move throughout the structure.

• This creates strong electrostatic attraction between the negatively charged electrons and positive metal cations

• In a pure metal, atoms are the same size and layers can slide over each other - so it bends / is malleable / ductile

• In alloy structures, atoms are different sizes, layers are distorted (can’t slide) and alloys are harder