Chapter 4, Problem 4.2KSP

Interpretation Introduction

Interpretation:

From the given options, it should be found the option which describes the why $Z_{eff}$ does not change significantly from top to bottom within a group.

Concept introduction:

Effective nuclear charge $Z_{eff}$, refers to the charge experienced by outer most electrons of a multi electron atom after taking into account the number of shielding electros that surrounds the nucleus.

First ionization energy:  It is the amount of energy required to remove one electron from a neutral atom.

Secondionization energy: It is the amount of energy required to remove another electron from an ion.