What is periodicity?

Periodicity refers to the periodic recurrence of properties and nature of elements.

This periodicity is based on the electronic configuration of elements in the modern periodic table.

The elements in the modern periodic table are placed in the order of increasing atomic number.

The elements are placed in such a way that elements with that a group constitutes of elements with the same valence shell electrons. It is because of this similarity that the elements show similar properties.

Such properties which vary as we move from left to right or top to bottom in the periodic table are called periodic properties because they keep recurring at regular intervals.

Periodicity refers to such trends or variations which re-occur in element properties with change or increase in atomic number.