Question

What is periodicity?

Answer 1

Periodicity means, something repeats after fixed interval. Periodicity means that if elements are arranged in an order, the properties of elements would repeat after some period.

In periodic table after every 8th element the properties of 1st. It is known as periodicity. E.g. properties of lithium and sodium relate with each other as they are in a periodic manner and so on goes with rest of periodic table .

Important periodic properties are:
• Atomic radius
• Ionization energy
• Electron affinity
• Electronegativity
• Metallic and non-metallic character

These trends became apparent to Mendeleev when he arranged the elements in order of increasing mass.