Metals
& Non-metals

Metals are usually lustrous, malleable, ductile, sonorous and good conductors with high melting points. Non-metals are usually dull, brittle and poor conductors. But watch the famous exceptions.

• With oxygen: metal + O₂ → metal oxide (basic). e.g. 2Cu + O₂ → 2CuO.
• With water: reactive metals react (Na violently, Mg slowly); many do not.
• With acids: metal + dilute acid → salt + hydrogen.
• With salt solutions: a more reactive metal displaces a less reactive one.

Metals can be ranked by how readily they react — the reactivity series. A metal higher in the series will displace one lower down from its salt solution. Try it:

A metal loses electrons (forming a positive ion) and a non-metal gains them (forming a negative ion). The opposite charges attract — an ionic (electrovalent) bond. e.g. Na → Na⁺ + e⁻ and Cl + e⁻ → Cl⁻, giving NaCl.

Metals occur as minerals; an ore is a mineral worth extracting from. How we extract depends on reactivity:

• Most reactive (K, Na, Ca, Mg, Al): electrolysis of molten compounds.
• Moderately reactive (Zn, Fe, Pb): roast/calcine the ore to the oxide, then reduce with carbon.
• Least reactive (Ag, Au): found native or extracted easily.

Corrosion (rust, tarnish) is prevented by painting, oiling, galvanising (zinc coat), or making alloys (e.g. stainless steel).