Question

which of the following statements is true about effective nuclear charge?

• A. $Z_{eff}$ decreases from top to bottom
• B. $Z_{eff}$ increases from top to bottom
• C. $Z_{eff}$ increases as we move from left to right in periodic table
• D. $Z_{eff}=Z\times \sigma$ (here $\sigma$ is screening constant

Answer 1

Answer: (A), (C)

$Z_{eff}$ decreases from top to bottom
$Z_{eff}$ increases as we move from left to right in periodic table

The periodic table tendency for effective nuclear charge: Increase across a period (due to increasing nuclear charge with no accompanying increase in shielding effect). Decrease down a group (although nuclear charge increases down a group, shielding effect more than counters its effect).