Question

Which is true about effective nuclear charge?

• A. Z_eff ⁼ Z- σ (Screening Constant)
• B. Z_eff increases as we move from left to right in the Periodic table
• C. Z_eff decreases from top to bottom
• D. Z_eff increases from top to bottom

Answer 1

The correct option is A

Z_eff ⁼ Z- σ (Screening Constant)

Remember the shielding effect or screening effect which reduces the effectiveness of interaction between the nucleus and the outermost electrons? So we consider the effective nuclear charge for the same reason.

Hence,

Effective nuclear charge = $Zeff=Z-\sigma$ (\sigma\ = Screening Constant).

Effective nuclear charge ($Zeff$) increases as we move from left to right in a period.