Question

The electronic configuration of copper (Z = 29) is

• A. [Ar] 3d$^9$4s$^2$
• B. [Ar] 3d$^{10}$4s$^1$
• C. [Ar] 3d$^8$4s$^2$
• D. [Ar] 3d$^{10}$4s$^2$

Hint:

Copper is an exception to the normal filling order and adopts a [Ar] 3d$^{10}$4s$^1$ configuration for stability.

Answer 1

The Correct Option is B

Step 1: Understand electronic configuration.
The electronic configuration of an atom is the distribution of its electrons among various orbitals. Copper (Cu) has an atomic number of 29.
Step 2: Apply the Aufbau principle.
- The configuration for Copper (Cu) should fill up orbitals starting from the lowest energy level. - However, copper is an exception because it prefers to have a fully filled 3d orbital. This leads to the configuration [Ar] 3d$^{10}$4s$^1$.
Step 3: Apply to the options.
Option (B) is the correct configuration for copper, where the 4s orbital has one electron and the 3d orbital is completely filled.
Final Answer: \[ \boxed{\text{[Ar] 3d}^{10}\text{4s}^1} \]