Metals and Non-metals

Metals are usually lustrous, malleable, ductile and good conductors of heat and electricity. Non-metals usually do not show these properties. There are exceptions, so exam answers should say 'generally' when comparing.

Metals react with oxygen to form metal oxides. Many metals react with water or acids, but their speed depends on reactivity. Non-metals usually form acidic or neutral oxides. The reactivity series helps predict which metal can displace another.

A metal atom can lose electrons to form a positive ion. A non-metal atom can gain electrons to form a negative ion. Oppositely charged ions attract strongly, so ionic compounds have high melting points and conduct electricity when molten or in solution.

Ores contain metals in combined form. Extraction depends on reactivity: very reactive metals need electrolysis, while less reactive metals can be reduced more easily. Corrosion is damage by reaction with the environment, and it can be reduced by painting, oiling, galvanising or alloying.