Effective Nuclear Charge ($$Z_{\text{eff}}$$) & Shielding

Formula: $$Z_{\text{eff}} = Z - \sigma$$

Concept: Determines the net electrostatic positive charge felt by valence electrons after factoring in the shielding constant ($$\sigma$$) provided by core shell electrons.

Notation:

• $$Z_{\text{eff}}$$ = Effective nuclear charge;
• $$Z$$ = Actual atomic number;
• $$\sigma$$ = Screening constant where shielding power order follows $$s > p > d > f$$