Question

How does atomic size change down the group and along a period in the modern periodic table and why?

Answer 1

• from left to right in a period atomic size decreases because in a period the elements have same number of valence shells but number of electrons increase from moving left to right / as electrons increases, the attraction of the electrons become more and atomic size decreases.

• on moving from top to bottom in a group atomic size increases because , along a period the number of shells increases