Non-metals

General characteristics

• Non-metals are elements that generally tend to gain, share or attract electrons during chemical reactions.
• They usually have high ionisation enthalpy and high electronegativity compared with metals in the same period.
• Solid non-metals are generally brittle, not malleable or ductile, and usually lack metallic lustre.
• Most non-metals are poor conductors of heat and electricity, but graphite conducts electricity and diamond conducts heat extremely well.
• Iodine is a lustrous non-metal, while graphite also has a metallic-looking sheen.
• Non-metals form mainly covalent compounds with one another and often form ionic compounds by gaining electrons from metals.
• Their oxides are commonly acidic or neutral; a few show mixed behaviour depending on oxidation state.

Physical states at ordinary conditions