Atoms share a pair of electrons on their outer-shells
Small molecules
There are strong covalent bonds within molecules, weak intermolecular forces between the molecules, Have low melting point because it doesn’t take much energy to overcome the small intermolecularforces, so they are either a gas or liquid at room temperature
Polymers
Have very large molecules with many atoms bonded together in a chain, they are solids at room temperature as they have a relatively high melting point because the intermolecular forces are strong
Giant covalent structures
There are lots of atoms and all are covalently bonded together, have high melting points as a lot of energy is needed to overcome the many strong covalent bonds between the atoms so they are solid at room temperature
Electricity
Covalently bonded molecules do not conduct electricity as they do not have charge or delocalised electrons
