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GCSE Chemistry · key term
The simplest whole-number ratio of atoms of each element in a compound.
Used by AQA, Edexcel and OCR
Specification 4.2.1.3 · Paper 1
A chemical formula showing the simplest whole-number ratio of the different atoms or ions in a compound.
Revise: Structure of Ionic CompoundsA giant ionic lattice contains no individual molecules, so its formula records the simplest whole-number ratio of its ions. This is an empirical formula.
Specification 1.44, 1.45, 1.46 · Paper 1, Paper 2
Revise: Empirical Formulae CalculationAn empirical formula gives the simplest whole-number ratio of those atoms.
The formula showing the simplest whole-number ratio of atoms of each element in a compound.
A formula showing the simplest whole-number ratio of atoms of each element in a compound.
Specification CM2.1iv, C2.1d, CM2.2iii, CM3.1i, CM3.4i, CM4.1i · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Empirical Formulae CalculationsThe empirical formula gives the simplest whole-number ratio of atoms in a compound.
A formula showing the simplest whole-number ratio of atoms or ions in a substance.
The simplest whole-number ratio of atoms of each element in a substance.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A formula showing the simplest whole-number ratio of atoms of each element in a compound.
Revise: Empirical formulaAn empirical formula instead gives their simplest whole-number ratio. It does not show how the atoms are arranged.
State that the result is an empirical formula: it gives the simplest whole-number ratio, not necessarily the actual numbers of atoms in a molecule.
When converting a molecular formula into an empirical formula, divide every subscript by the same highest common factor. Do not divide the element symbols or remove an element.
For a molecular formula, multiply every subscript in the empirical formula by the whole-number multiplier, including any unwritten subscript of 1.
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