We’re being asked to predict the effective nuclear charge (Zeff) for the outermost electrons in Rb atom based on the calculations for Na and K using Slaters rules
Recall that the effective nuclear charge is the force exerted by the nucleus onto an electron and is given by:
where Z = nuclear charge or atomic number and S = shielding constant.
The shielding constant can be calculated using Slater’s Rules:
For ns and np electrons:
1. Each electron in the same group will contribute 0.35 to the S value. A 1s electron contributes 0.30 to the S value of another 1s electron.
2. Each electron in the n–1 group contributes 0.85 to the S value.
3. Each electron in the n–2 or greater group contributes 1.00 to the S value.
For nd and nf electrons:
1. Each electron in the same group will contribute 0.35 to the S value.
2. Each electron in the groups to the left contributes 1.00 to the S value.
For this problem, we will determine the Zeff for Na and K using the following steps:
Step 1: Determine the atomic number.
Step 2: Determine the electron configuration and group them by n-values.
Step 3: Calculate for the shielding constant using Slater's Rules.
Step 4: Calculate for Zeff.
Then predict the Zeff for Rb