1118 elements, in order
The periodic table lists all 118 known elements in order of atomic number: the number of protons in an atom.
periodic tableatomic number
Lesson 20.1 notes
Groups and periods
How the periodic table is arranged: groups, periods, families, metals and non-metals, and symbols.
2Groups and periods
A group is a column. A period is a row. Elements in the same group have similar properties.
groupperiod
3Finding an element
Go down the group and across the period: they meet at the element. Group 7, period 3 is chlorine.
4Metals and non-metals
Most elements are metals, on the left and in the middle. The non-metals are at the top right, beyond the staircase line.
metalnon-metal
5Families
Group 1 is the alkali metals, Group 7 the halogens and Group 0 the noble gases. The middle block is the transition metals.
alkali metalshalogensnoble gases
6Across a period
Going across a period, the elements change from metals on the left to non-metals on the right.
7Symbols
Every element has a symbol: a capital letter, sometimes followed by a small one. Some come from Latin: Na from natrium, Fe from ferrum.
symbol
Explore: Periodic table explorer
Tap any element to see its card. Change the colours to show metals and non-metals, families, or solids, liquids and gases.
Common mistake: Groups are columns; periods are rows
It is easy to mix them up. A group goes down the table, like Group 1: lithium, sodium, potassium. A period goes across, like period 3: sodium to argon.
Remember
- The periodic table is in order of atomic number. Columns are groups; rows are periods.
- Elements in the same group have similar properties.
- Metals are on the left and in the middle. Non-metals are at the top right, plus hydrogen.
Going further at GCSE