The filling of degenerate orbital by electrons is governed by ………. rule

Options

A. Hund’s
B. Aufbau
C. Pauli’s
D. All of the above

Explanation

To solve the question regarding the filling of degenerate orbitals by electrons, we need to identify the rule that governs this process. The correct answer is the "Hund's Rule."

### Step-by-Step Solution:

1. **Understanding Degenerate Orbitals**:
- Degenerate orbitals are orbitals that have the same energy level. For example, the three p orbitals (px, py, pz) are degenerate because they all have the same energy.

2. **Filling of Electrons in Degenerate Orbitals**:
- When electrons are added to degenerate orbitals, they will first fill each orbital singly before pairing up. This is a key aspect of Hund's Rule.

3. **Hund's Rule**:
- According to Hund's Rule, electrons will occupy degenerate orbitals singly with the same spin (parallel spins) until all orbitals in that subshell are half-filled. Only after each orbital has one electron will the electrons start to pair up.

4. **Conclusion**:
- Therefore, the filling of degenerate orbitals by electrons is governed by Hund's Rule, which states that electrons will fill degenerate orbitals singly first and with parallel spins.

### Final Answer:
The filling of degenerate orbitals by electrons is governed by **Hund's Rule**.

---