Question

19. How does atomic size charge in moving across a period from left to right AND why? (Be sure your answer refers to the shielding/screening effect as well as effective nuclear charge.)

Answer 1

Across a period from left to right atomic size can be decrease, due to increment in effective nuclear charge and density of electron cloud around the nucleus. In this mean time, the electro static actraction might be increased in between atomic nucleus and outer orbitals of an atom due to increment in number of electrons. In periods left to right , the shielding effect may not increase that much compared to nucleus charge.

In general, the atomic size will be decrease in periods from left to right