Which of the following configuration is incorrect ?

Options

A. `1s^(2)2s^(2)2p_(x)^(2)2p_(y)^(2)2p_(z)^(0)`
B. `1s^(2)2s^(2)2p_(x)^(1)2p_(y)^(1)2p_(z)^(0)`
C. `1s^(2)2s^(2)2p_(x)^(1)2p_(y)^(1)2p_(z)^(1)`
D. `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5)4s^(1)`

Explanation

To determine which of the given electron configurations is incorrect, we will analyze the configurations based on the principles of electron filling, specifically Hund's Rule and the Pauli Exclusion Principle.

### Step-by-Step Solution:

1. **Understanding Electron Configuration**:
- Electron configurations describe the distribution of electrons in an atom's orbitals.
- Electrons fill orbitals in a specific order based on energy levels and subshells.

2. **Identify the Given Configuration**:
- The first configuration provided is: **1s², 2s², 2p², 2py, 2pz⁰**.

3. **Analyzing the 2p Subshell**:
- The 2p subshell can hold a maximum of 6 electrons (2 in each of the three orbitals: 2px, 2py, and 2pz).
- According to Hund's Rule, electrons must fill each orbital singly before pairing begins.

4. **Applying Hund's Rule**:
- In the given configuration, we have 2 electrons in the 2p subshell (2p²).
- The correct filling should be:
- 1 electron in 2px (1st electron)
- 1 electron in 2py (2nd electron)
- 2pz should remain empty (0 electrons).
- However, the configuration states **2py** is filled with 2 electrons and **2pz** has 0 electrons, which violates Hund's Rule.

5. **Conclusion**:
- The configuration **1s², 2s², 2p², 2py, 2pz⁰** is incorrect because it violates Hund's Rule by pairing electrons in the 2py orbital before filling the 2px orbital singly.

### Final Answer:
The incorrect configuration is **1s², 2s², 2p², 2py, 2pz⁰**.

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