Question

Lithium atom is smaller potassium atom
Give reason.​

Answer 1

Potassium possesses more number of valence shells than lithium, so lithium is smaller than potassium atom. As it is clear, that chlorine is placed after sulphur so it has a smaller size and thus, its tendency to gain electron is- more than S.

Answer 2

Answer:

The atomic number of Lithium is 3, and it is in the 2nd period of the periodic table. So it has 3 protons and 4 neutrons in the nucleus. And it is in the 2nd period, so it has 2 outer shells.

But, the atomic number of Potassium is 19, and it is in the 4th period of the periodic table. So it has 19 protons and 20 neutrons in the nucleus. And it is in the 4th period, so it has 4 outer shells.

So, for the above mentioned reasons, the atom of Lithium is smaller than the atom of Potassium.