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

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

Concept: Represents the net positive charge experienced by an electron in a multi-electron atom, accounting for the shielding effect of intervening core electrons.

Notation:

• $$Z_{\text{eff}}$$ = Effective nuclear charge;
• $$Z$$ = Atomic number (actual nuclear charge);
• $$\sigma$$ = Screening or shielding constant calculated via Slater's rules.