Electronic configurations of `Cu ( Z = 29)` is

Options

A. `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(6), 3p^(6), 4s^(2), 3d^(9)`
B. `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(6), 3d^(10), 4s^(1)`
C. `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(6), 4s^(2), 4p^(6), 5s^(2), 5p^(1)`
D. `1s^(2), 2s^(2), 2p^(6), 3s^(2), 3p^(6), 4s^(2), 4p^(6), 3d^(3)`

Answer

To determine the electronic configuration of copper (Cu) with atomic number 29, we can follow these steps:

### Step 1: Understand the Atomic Number
The atomic number of copper (Cu) is 29, which means it has 29 electrons.

### Step 2: Fill the Orbitals According to the Aufbau Principle
We will fill the orbitals in the order of increasing energy levels. The order of filling is as follows:

1. 1s
2. 2s
3. 2p
4. 3s
5. 3p
6. 4s
7. 3d

### Step 3: Fill the Orbitals
We fill the orbitals with electrons:

- **1s** can hold 2 electrons: 1s²
- **2s** can hold 2 electrons: 2s²
- **2p** can hold 6 electrons: 2p⁶
- **3s** can hold 2 electrons: 3s²
- **3p** can hold 6 electrons: 3p⁶
- **4s** can hold 2 electrons: 4s²
- **3d** can hold 10 electrons: 3d¹⁰

### Step 4: Count the Electrons
Adding these up:
- 1s² + 2s² + 2p⁶ + 3s² + 3p⁶ + 4s² + 3d¹⁰ = 2 + 2 + 6 + 2 + 6 + 2 + 10 = 30 electrons.

However, we need to adjust for copper, which has 29 electrons.

### Step 5: Adjust for Stability
Copper is an exception to the standard filling order due to stability reasons. Instead of filling the 3d orbital to 9 electrons and the 4s orbital to 2 electrons, copper prefers to have a filled 3d orbital and a half-filled 4s orbital. Thus, we have:

- 3d¹⁰ (fully filled)
- 4s¹ (half-filled)

### Final Electronic Configuration
Therefore, the electronic configuration of copper (Cu) is:
\[ \text{[Ar]} \, 3d^{10} \, 4s^{1} \]

### Conclusion
The correct electronic configuration for copper (Cu, Z = 29) is:
\[ \text{1s}^2 \, \text{2s}^2 \, \text{2p}^6 \, \text{3s}^2 \, \text{3p}^6 \, \text{4s}^1 \, \text{3d}^{10} \]