The Periodic Table
How the elements are organised — and why the pattern matters.
01Arranging the ElementsSee how Mendeleev ordered elements by atomic mass and properties.Read lesson →02Groups and PeriodsRead the table's columns and rows and what they tell you.Read lesson →03Metals and Non-metalsCompare the properties of metals with those of non-metals.Read lesson →04Trends in GroupsPredict how reactivity changes down Group 1 and Group 7.Read lesson →