The orbital diagram in which both Pauli's exclusion principle and Hund's rule are violated , is :

Options

A.
B. (b)
C. (c)
D. (d)

Answer

To solve the question regarding the orbital diagram in which both Pauli's exclusion principle and Hund's rule are violated, we can follow these steps:

### Step 1: Understand the Principles
- **Pauli's Exclusion Principle**: States that no two electrons in an atom can have the same set of four quantum numbers. This means that in an orbital, if two electrons are present, one must have an up spin and the other must have a down spin.
- **Hund's Rule**: States that for degenerate orbitals (orbitals of the same energy), one electron must occupy each orbital singly with the same spin before any pairing occurs.

### Step 2: Analyze the Given Diagrams
We need to evaluate the provided orbital diagrams to see which one violates both principles.

1. **First Diagram**: Shows two electrons in an s orbital with one up spin and one down spin. This follows both principles.
2. **Second Diagram**: Shows three p orbitals filled correctly according to Hund's rule and Pauli's exclusion principle. This also follows both principles.
3. **Third Diagram**: Shows one electron in an s orbital with up spin and another with down spin, but in the p orbitals, pairing occurs before all orbitals are singly occupied. This violates Hund's rule but follows Pauli's exclusion principle.
4. **Fourth Diagram**: Shows two electrons with the same spin in an orbital, which violates Pauli's exclusion principle, and also does not fill the degenerate orbitals singly first, violating Hund's rule.

### Step 3: Identify the Correct Diagram
The diagram that violates both Pauli's exclusion principle and Hund's rule is the **Fourth Diagram**. In this diagram, both electrons have the same spin, violating Pauli's principle, and the degenerate orbitals are not filled singly first, violating Hund's rule.

### Conclusion
The answer to the question is that the orbital diagram in which both Pauli's exclusion principle and Hund's rule are violated is the **Fourth Diagram**.

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