The value of n (i.e. principal qunatum number ) for the valence shell of palladium is (atomic number =46):

Explanation

To find the principal quantum number (n) for the valence shell of palladium (atomic number = 46), we can follow these steps:

### Step-by-Step Solution:

1. **Determine the Atomic Number**:
- The atomic number of palladium (Pd) is 46. This means it has 46 electrons.

2. **Write the Electronic Configuration**:
- Start filling the orbitals according to the Aufbau principle:
- 1s² (2 electrons)
- 2s² (2 electrons)
- 2p⁶ (6 electrons)
- 3s² (2 electrons)
- 3p⁶ (6 electrons)
- 4s² (2 electrons)
- 3d¹⁰ (10 electrons)
- 4p⁶ (6 electrons)
- 5s² (2 electrons)
- 4d⁸ (8 electrons)
- The complete electronic configuration of palladium is:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d⁸

3. **Identify the Valence Shell**:
- The valence shell is defined as the outermost shell that contains electrons. For palladium, the outermost shell is the 4th shell (n=4) because the last filled subshell is 4d.

4. **Determine the Principal Quantum Number (n)**:
- The principal quantum number (n) corresponds to the highest energy level that has electrons. In this case, the last filled subshell is 4d, which indicates that n = 4.

5. **Final Answer**:
- Therefore, the value of n for the valence shell of palladium is **4**.