Question

If effective nuclear charge of F(Z=9) is X and effective nuclear charge of Li (Z=3) is Y then find the value of |X-Y|

Answer 1

• $Z_{eff}$ for a 2p electron in fluorine - (1s2)(2s2,2p5); $Z_{eff}$ = 9 – (0.35 x 6 + 0.85 x 2) = 9- 3.8 = 5.2 for a valence electron.
• $Z_{eff}$ for 2s electron in lithium (1s2 2s2) ; $Z_{eff}$ = 2 - 1.7 = 1.3 for a valence electron
• Therefore, |X -Y|=|5.2 - 1.3| = 3.9