Question

In which of the following pairs, both the elements do not have \( (n-1)d^{10}ns^2 \) configuration?

• A. Zn, Cd
• B. Cd, Hg
• C. Ag, Cu
• D. Cu, Zn

Hint:

Remember, silver (Ag) and copper (Cu) have unusual electron configurations where the 4s orbital only has one electron. This is a special case due to the stability of fully filled or half-filled \(d\)-orbitals.

Answer 1

The Correct Option is C

For transition metals, the electron configuration typically follows the (n-1)d^{10}ns^2 pattern. Let’s look at the electron configurations of the pairs:
- Zinc (Zn): \( [Ar] 3d^{10} 4s^2 \) – follows the configuration.
- Cadmium (Cd): \( [Kr] 4d^{10} 5s^2 \) – follows the configuration.
- Silver (Ag): \( [Kr] 4d^{10} 5s^1 \) – does not follow the configuration due to a single electron in the 5s orbital.
- Copper (Cu): \( [Ar] 3d^{10} 4s^1 \) – does not follow the configuration due to a single electron in the 4s orbital.
Thus, the pair that does not follow the typical (n-1)d^{10}ns^2 configuration is Ag and Cu.
Therefore, the correct answer is:
\[ \text{(3) Ag, Cu} \]