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wise otter.Chemistry
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Bonding and Structure

Topic 4 of 5

Metals and alloys

Recognize metals and alloys and connect their properties to their arrangement.

O-Level 2026 SEC G3 2027

Metals and alloys: properties from arrangement

Recognize a metal and an alloy, then connect structure to their different behaviour.

Metals generally have high melting and boiling points, conduct heat and electricity, and are malleable: they can be hammered into shape. Most are solids at room temperature. These are general patterns, not rules without exceptions.

An alloy is a mixture of a metal with other elements. Brass contains copper and zinc. Stainless steel contains iron and chromium, with other elements depending on its composition. Unlike a compound, an alloy need not have a fixed ratio of elements.

Pure metal: regular layers

Equal-sized atoms in regular rowsThirteen equal-sized particle symbols are arranged in regular offset rows. This compares atomic sizes and arrangement; the delocalised electrons are omitted.
One type of atom, arranged in regular layers.

Alloy: disrupted layers

A different-sized atom distorts the regular arrangementThirteen particle symbols include one larger amber atom. The smaller neighbouring atoms are displaced, so the layers are less regular. This compares atomic sizes and arrangement; the delocalised electrons are omitted.
Different-sized atoms disrupt the regular arrangement.

A simplified substitutional alloy, not to scale. Other alloys may contain smaller atoms in gaps.

A pure metal contains one type of atom. An alloy contains more than one; differently sized circles represent its different constituent atoms.