9.1 Properties of metals

2026 Syllabus Objectives

  1. Core: Compare the general physical properties of metals and non-metals, including:

    • (a) thermal conductivity
    • (b) electrical conductivity
    • (c) malleability and ductility
    • (d) melting points and boiling points

  2. Core: Describe the general chemical properties of metals, limited to their reactions with:

    • (a) dilute acids
    • (b) cold water and steam
    • (c) oxygen

Distribution of Metals in the Periodic Table 🗺️

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Most elements in the Periodic Table are metals - approximately 70 out of 118 known elements can be classified as metals.

Position in the Periodic Table:

  • Metals are positioned to the left of the Periodic Table
  • Non-metals lie to the right of the table
  • This transition from metals to non-metals (left to right) represents one of the major trends in the structure of the Periodic Table

Key groups of metals:

  • Reactive metals: Groups I and II (alkali metals and alkaline earth metals)
  • Transition metals: Central block of the Periodic Table
  • Other metals: To the right of the transition block

Bonding and structure:

  • Metals are held together by metallic bonding
  • This type of bonding gives rise to many characteristic properties that metals have in common
  • However, there is wide variation in the level of these properties when examining different metals in detail

Example: Many metals have high density (e.g., iron), but the alkali metals (Group I) have low densities.

Physical Properties of Metals and Non-metals ⚡

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The physical properties of metals arise directly from their crystalline structure with metal atoms packed in regular layers that can slide over each other.

Key Physical Properties

1. Electrical Conductivity 🔌

Definition: The ability to conduct electricity.

Metals:

  • All metals conduct electricity, even mercury (which is liquid at room temperature)
  • This is the best way to identify whether a substance is a metal or non-metal

Non-metals:

  • Generally do not conduct electricity (they are insulators)
  • Exception: Graphite is a non-metal that conducts electricity

2. Thermal Conductivity 🔥

Definition: The ability to conduct heat.

Metals:

  • Metals conduct heat well
  • This good thermal conductivity results from the structure of metals
  • When one part of a metal is heated, the metal atoms vibrate more strongly
  • This increased vibration is passed throughout the whole metal structure

Mechanism of thermal conduction:

  • Atoms near the heat source vibrate faster
  • These faster-vibrating atoms collide with slower-vibrating atoms further away
  • Energy is transferred through the metal structure

Non-metals:

  • Generally poor thermal conductors
  • Exception: Diamond conducts heat strongly

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