# Calculate the effective nuclear charge felt by a 3d electron of chromium atom (z = 24).

1.5k views

closed
Calculate the effective nuclear charge felt by a 3d electron of chromium atom (z = 24).
1. 3.90
2. 4.60
3. 3.55
4. 4.20

by (54.0k points)
selected

Correct Answer - Option 2 : 4.60

The correct answer is 4.60.

• The formula for calculating the effective nuclear charge for a single electron is:
• Zeff= Z − S
• Zeff is the effective nuclear charge.
• Z is the atomic number.
• S is the average amount of electron density between the nucleus and the electron.
• The atomic number of chromium is 24.
• S requires the use of Slater’s Rules to determine the value.
• For chromium, the electron configuration is (1s2) (2s2, 2p6) (3s2 3p6) (3d5) (4s1).
• Any electrons to the right of the electron of interest contain no shielding value.
• Therefore (4s)1do not contribute since we are focusing on the 3d orbital.
• Electrons in the same group as the electron of interest shields 0.35 nuclear charge units.
• For d or f electrons: all electrons shield 1.00 unit.
• Zeff =24−(4×0.35)−(18×1).
• Zeff = 24 - 19.4 = 4.6