Final answer:
In potassium, the effective nuclear charge (Zeff) experienced by an electron is estimated using a simplified model of electron shielding. The actual nuclear charge is reduced by an estimated amount of shielding caused by the other electrons, with specific values typically used for electrons within the same shell and inner shells for these calculations.
Step-by-step explanation:
The effective nuclear charge (Zeff) on an electron in a multi-electron atom like potassium (K) can be estimated using the concept of electron shielding. Potassium has an atomic number of 19, which means it has 19 protons in its nucleus and, when neutral, 19 electrons. The electron configuration of potassium is [Ar]4s¹. In this configuration, the valence electron in the 4s orbital experiences shielding from the inner electrons that are closer to the nucleus.
Although the exact calculation of Zeff requires complex quantum mechanical calculations, a simplified model assumes that each electron in the same shell as the valence electron contributes a shielding effect of 0.35, each electron in the n-1 shell contributes 0.85, and each electron in the n-2 or a lower shell contributes 1.00 to the shielding effect. Using these values, the effective nuclear charge felt by an electron in the 4s orbital of potassium would be lower than the actual nuclear charge due to the shielding effect of the other electrons.
Thus, the Zeff calculation involves subtracting the estimated shielding from the actual nuclear charge. A detailed calculation would account for the specific distribution and contribution of each inner electron's shielding effect, with the general trend being that the Zeff for an outer electron is smaller than for an inner electron due to increased shielding by other electrons.