AQA GCSE Chemistry · 8462
Specification 4.1.1.1 · Paper 1
- Revise: Compounds and Chemical Equations
A combination of element symbols and numbers showing which elements a substance contains and their fixed proportions.
Loading…
Loading…
Loading…
GCSE Chemistry · key term
A combination of element symbols and small numbers showing which elements a substance contains and their relative numbers of atoms.
Used by AQA, Edexcel and OCR
Specification 4.1.1.1 · Paper 1
A combination of element symbols and numbers showing which elements a substance contains and their fixed proportions.
Specification 0.1 · Paper 1, Paper 2
Symbols and numbers showing the elements present in a substance and the numbers or simplest ratio of their particles.
Revise: Formulae of Elements and IonsA chemical formula uses these symbols to identify a substance and show its composition. For example, H₂O contains hydrogen and oxygen, with two hydrogen atoms for each oxygen atom. A formula is therefore more than an abbreviated name: CO and CO₂ describe different compounds because their carbon-to-oxygen ratios differ.
Specification C3.1a, C3.1b, C3.1c · Paper 1 (Foundation), Paper 3 (Higher)
Symbols and subscripts showing which elements a substance contains and the number or ratio of their atoms or ions.
Revise: Chemical FormulaeA chemical formula combines symbols with small numbers called subscripts. The subscript applies to the symbol immediately before it; if there is no subscript, the number is one. In H₂O, there are two hydrogen atoms and one oxygen atom.
A combination of chemical symbols and subscripts showing the elements in a substance and their relative numbers of atoms or ions.
A representation of a substance that shows its elements and how many atoms of each are present, or their simplest ratio.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A symbolic representation showing which elements a substance contains and the number of atoms of each element in one molecule, or their ratio in the substance.
Revise: Chemical formulaeA chemical formula uses these symbols to describe a substance. It tells you which elements are present and how many atoms of each element occur in a molecule. A formula is not an abbreviation that can be written in several different ways: changing a symbol, its capitalisation or a subscript can change the substance represented.
A representation of a substance using element symbols and numbers to show the relative numbers of its atoms.
Symbols and small numbers showing which elements are present in a substance and how many atoms there are in a molecule, or the simplest ratio of ions in an ionic compound.
A representation of a substance using element symbols and numbers to show which atoms it contains and their proportions.
A symbolic representation that identifies the elements in a substance and shows their relative numbers or ratio.
Write numbers in a chemical formula as subscripts. A normal-sized or superscript number does not correctly represent the formula.
Create a free account to read GCSE Chemistry revision notes for your exam board and track your progress.