Periodic table

The periodic table. An 18-column by seven-row grid of the elements arranged by increasing atomic number. The columns are called groups. Elements in each group tend to have similar properties.

All the chemical elements are arranged in the periodic table in horizontal rows (periods) in order of increasing atomic number and also in vertical columns (groups).

Elements in the same group have similar reactivities resulting from a common number of outer electrons.

This allows chemists to make predictions about:

  • reactivity
  • physical properties
  • type of bonding

Within the first 20 elements there are various different types of bonding displayed, moving from metallic to non-metallic across the periodic table.