Malleability

Summary: Malleability is the ability of a material, especially a metal, to be hammered or pressed into a new shape without breaking, explained by layers of positive ions sliding over each other while the sea of delocalised electrons maintains the metallic bonding. Tags: igcse chemistry Created: 2026-07-18

Malleability is the ability of a material to be hammered, rolled, or pressed into shape without breaking or shattering, and it is a characteristic physical property of metals. At the particle level (Syllabus 2.7 Supplement 2(b)), malleability is explained by the structure of the Giant Metallic Lattice: when a force is applied, layers of positive metal ions slide over one another, while the surrounding “sea” of delocalised electrons moves with them and maintains the electrostatic attraction that holds the structure together. Because Metallic Bonding is non-directional — each ion is attracted to the electron sea as a whole rather than to fixed neighbours — the bonding is not broken when the ions change position, so the metal simply takes on a new shape. This behaviour contrasts sharply with the brittleness of ionic compounds, where shifting the layers of a giant ionic lattice brings like-charged ions alongside each other and the resulting repulsion splits the crystal. Malleability, together with Ductility, strength, and conductivity, underpins many practical Uses of Metals, from car body panels to aluminium foil.

Particle-Level Explanation

In a Giant Metallic Lattice, the positive ions are arranged in regular layers surrounded by delocalised electrons. When a metal is struck or pressed:

1. A layer of positive ions slides relative to the layer beneath it.
2. The delocalised electrons redistribute instantly around the ions in their new positions.
3. The electrostatic attraction between the ions and the electron sea is re-established — effectively it is never lost.
4. The metal holds its new shape instead of cracking.

The key idea is that metallic bonding acts between each ion and the mobile electron sea, not between specific pairs of particles, so sliding does not break the bonding.

Contrast with Brittle Ionic Lattices

In an ionic solid (see Ions and Ionic Bonds), the rigid alternation of + and − charges means even a small displacement of one layer places positive ions next to positive ions and negative next to negative. The layers repel and the lattice cleaves apart, which is why salts like sodium chloride are brittle crystalline solids while metals can be beaten into sheets.

Everyday Significance

Malleability is exploited whenever a metal must be shaped by force rather than melting:

• Aluminium is rolled into thin foil and pressed into drinks cans.
• Steel is stamped into car body panels and rolled into sheets.
• Gold, the most malleable metal, can be beaten into gold leaf only a few hundred atoms thick.
• Copper is shaped into pipes and containers (see Uses of Metals).

Alloys are generally less malleable than pure metals: atoms of different sizes disrupt the regular layers, making it harder for them to slide over each other — which is why alloys such as brass and steel are harder and stronger than their pure component metals.

Sources

• Cambridge IGCSE Chemistry 0620 Syllabus (2023-2025) — Section 2.7 Metallic bonding, Supplement 2(b), Cambridge Assessment International Education

Common Misconceptions