Question

The effective nuclear charge for the outermost electron of oxygen atom is

• A. 4.55
• B. 5.35
• C. 6.68
• D. None of these

Answer 1

The correct option is A 4.55

The expression for the effective nuclear charge $Z^{\ast }$ is
$Z^{\ast }=Z-S$
Here, Z is the nuclear charge and S is the shielding constant.

For oxygen $Z=8$ and $S=3.45=2\times 0.85+5\times 0.35$
Hence, $Z^{\ast }=Z-S=8-3.45=4.55$

Hence, the effective nuclear charge for oxygen atom is 4.55.