Elements are arranged in order of increasing atomic number (number of protons).
Groups are vertical columns. Periods are horizontal rows.
Group 1 runs down a column: lithium, sodium and potassium.
First 20 elements only. Group numbers use the GCSE 1–7 and 0 convention. Later elements are omitted.
Metals are on the left and in the centre. Non-metals are mainly on the right. Hydrogen is a non-metal, even though it sits on the left.
A map of the table’s shape. The grey staircase contains borderline elements, often called metalloids. The two rows shown below are metals.
Group 1: alkali metals. Far left, excluding hydrogen. Examples: lithium, sodium and potassium.
Group 7: halogens. Next to the far-right column. Examples: fluorine, chlorine and bromine.
Group 0: noble gases. Far right. Examples: helium, neon and argon.
Period number = number of occupied electron shells.
Group number (1–7) = number of outer-shell electrons.
Sodium is 2,8,1: 3 occupied shells, so Period 3; 1 outer electron, so Group 1.
Elements in the same group have similar chemical properties because their outer electron arrangements are similar.
For example, lithium (2,1), sodium (2,8,1) and potassium (2,8,8,1) all have 1 outer electron.
Order: increasing atomic number.
Metals: left and centre. Non-metals: mainly right, plus hydrogen.
Group 1: alkali metals. Group 7: halogens. Group 0: noble gases.
Groups: columns; similar chemical properties.
Periods: rows; number of occupied shells.
Find the group. Find the period.
Groups go down. Periods go across.
One point for each answer you get right first time.
No timer. Take your time and use a clue whenever you need one.