IGCSE and GCSE periodic table

For Cambridge IGCSE (0620), Edexcel IGCSE (4CH1), and AQA and Edexcel GCSE Chemistry. Click any element for its atomic number, relative atomic mass, group and period.

  • Metals
  • Non-metals

Hydrogen (H)

Atomic number
1
Relative atomic mass
1
Group
Group 1 (hydrogen is a non-metal)
Period
1
Type
Non-metal
1
2
3
4
5
6
7
0
57–71
89–103

Relative atomic masses are rounded as on IGCSE data sheets; values in square brackets are the mass number of an element with no stable isotope. Boron, silicon, germanium, arsenic, antimony and tellurium are semi-metals and are shown with the non-metals.

How to read the periodic table

Each element has an atomic number, the number of protons in its nucleus, and elements are arranged in order of increasing atomic number. The relative atomic mass is the average mass of its atoms compared with carbon-12, so it is roughly the number of protons plus neutrons. Read more in atomic structure and the periodic table.

A vertical column is a group. Elements in the same group have the same number of outer-shell electrons, which is why they react in similar ways. For Groups 1 to 7 the group number is the number of outer electrons; Group 0 atoms have full outer shells. A horizontal row is a period, and the period number is the number of electron shells in use. See arrangement of elements, or for Edexcel, groups and periods in Edexcel IGCSE Chemistry.

Trends you are examined on

Group 1 metals get more reactive going down the group; Group 7 halogens get less reactive going down, and a more reactive halogen displaces a less reactive one from its salt. Noble gases are unreactive because their outer shells are full. Transition elements form coloured compounds, act as catalysts and have high densities. Our post on Group 7 halogen trends works through the exam-style questions.

How to use the periodic table in IGCSE exams

Cambridge IGCSE and Edexcel IGCSE both give you a printed periodic table in the exam, so you do not need to memorise masses or atomic numbers. You do need to be fast at using it. These are the five jobs it does in a paper:

  1. Protons and electrons. The atomic number gives both for a neutral atom. Sodium is 11, so it has 11 electrons, arranged 2,8,1: period 3, Group 1.
  2. Neutrons. Subtract the atomic number from the mass number. For most elements the relative atomic mass, rounded, is the mass number of the commonest isotope; chlorine (35.5) is the usual exception.
  3. Relative formula mass. Add the relative atomic masses: for carbon dioxide, Mr = 12 + (2 × 16) = 44.
  4. Ion charges. Group 1 forms 1+ ions, Group 2 forms 2+, Group 3 forms 3+, Group 6 forms 2− and Group 7 forms 1−. Metals are on the left, non-metals on the right.
  5. Unfamiliar elements. Questions on rubidium or astatine expect you to apply the group trend: rubidium reacts more vigorously with water than potassium, and astatine is less reactive than iodine.

Practise with this table, then print it for revision.