Formation of covalent bonds
- Non-metal atoms can share electrons with other non-metal atoms to obtain a full outer shell of electrons
- When atoms share pairs of electrons, they form covalent bonds
- Covalent bonds between atoms are very strong
- Covalently bonded substances may be simple molecular structures or giant covalent structures
- Simple molecular structures include oxygen and water
- Giant covalent structures include diamond and graphite
- Shared electrons are called bonding electrons and occur in pairs
- Electrons on the outer shell which are not involved in the covalent bond(s) are called non-bonding electrons
Covalent bonding
Two chlorine atoms share one electron each to form a covalent bond with a shared pair of electrons
Examiner Tip
A key difference between covalent bonds and ionic bonds is that in covalent bonds the electrons are shared between the atoms, they are not transferred (donated or gained) and no ions are formed.