Question

Effective nuclear charge, Zeff, is defined as:

Answer 1

Answer:

The effective nuclear charge for a valence electron in oxygen atom: $Z_{eff} = 4.55$

Explanation:

Effective nuclear charge  $[Z_{eff}]$ is the net nuclear charge experienced by the electron in a given atom. It is always less than the actual charge of the nucleus [Z], due to shielding by electrons in the inner shells.

It is equal to the difference between the actual nuclear charge or the atomic number (Z) and the shielding constant (s).  

$\Rightarrow Z_{eff} = Z - s$

For an oxygen atom-

Electron configuration: (1s²) (2s² 2p⁴)

The atomic number (actual nuclear charge): Z = 8

The shielding constant (s) for a valence electron can be calculated by using the Slater's rules:

⇒ s = 5 × 0.35 + 2 × 0.85 = 1.75 + 1.7 = 3.45

Therefore, the effective nuclear charge for a valence electron in oxygen atom is:

$Z_{eff} = Z - s = 8 - 3.45 = 4.55$

Therefore, the effective nuclear charge for a valence electron in oxygen atom: $Z_{eff} = 4.55$