Question

calculate the screening constant and effective nuclear charge of 4s electron in Cu(Z=29) atom

Answer 1

Answer:

Screening Constant ( $\sigma$ ) = 25.3

Effective Nuclear Charge ( $Z_{eff}$ ) = 3.7

Explanation: We are given Cu element having atomic number 29.

Screening constant and effective nuclear charge can be calculated by using the following steps:

Step 1: Calculation for screening constant, $\sigma$

• Filling the electrons according to the Aufbau's principle in the order: (1s) (2s, 2p) (3s, 3p) (3d) (4s, 4p) (4d) (4f) (5s, 5p) (5d)...      $Cu(Z=29)=1s^22s^22p^63s^23p^63d^{10}4s^1$
• Shielding constant is formed as the sum of contributions of electrons.
• As the electron is present in 4s orbital, the contribution of every electron present in (n-1) shell will be 0.85 and contribution of every electron in (n-2) shell will be 1.0

                       $\sigma (4s)= (18\times 0.85)+(10\times 1.0)$

                       $\sigma=25.3$

Step 2: Calculation of Effective nuclear charge, $Z_{eff}$

          $Z_{eff}=Z-\sigma$

          $Z=29$

          $Z_{eff}=29-25.3$

          $Z_{eff}=3.7$