Reactions and the periodic table

Metals and non-metals are found in different parts of the periodic table. They have different electronic structure, and this influences the way in which they react.

Metals and non-metals in the periodic table

In the modern periodic table, elements are arranged according to their atomic number.

Period table with metals in red and non-metals in yellow.The modern periodic table with some elements left out for simplicity

In the periodic table:

  • the metal elements are placed on the left-hand side
  • the non-metal elements are placed on the right-hand side

You can imagine a zig-zag line, starting at B-Al-Si, separating metals from non-metals.

Structure of the atoms of metals and non-metals

The periodic table shows that metals are found in groups 1, 2 and 3. These metals will have 1, 2 or 3 electrons in the outer shell.

The outer shell of a metal is, therefore, less than half full of electrons. For this reason, metals are more likely to lose electrons to form a full outer shell.

Non-metals are mostly found in groups 5, 6 and 7. These non-metals will have 5, 6 or 7 electrons in the outer shell.

The outer shell of a non-metal is, therefore, more than half full of electrons. For this reason, non-metals are more likely to gain electrons to form a full outer shell.

Reactivity of metals and non-metals

The pattern of reactivity of the group 1 elements and the group 7 elements shows the general pattern for the reactivity of other groups.

GroupsTypePattern of reactivity
1, 2, 3MetalReactivity increases down the group
5, 6, 7Non-metalReactivity decreases down the group

An explanation of the patterns of reactivity in group 1 and 7 elements in the periodic table