Which of the following electronic configuration is not possible?

Options

A. `1s^(2), 2s^(2), 2p^(6)`
B. `1s^(2), 2s^(2), 2p^(7)`
C. `1s^(2), 2s^(2)`
D. `1s^(2), 2s^(2), 2p^(5)`

Explanation

To determine which of the given electronic configurations is not possible, we need to understand the maximum number of electrons that can be accommodated in each type of subshell.

### Step-by-Step Solution:

1. **Understanding Electron Configuration**:
- Each subshell (s, p, d, f) has a specific number of orbitals, and each orbital can hold a maximum of 2 electrons.
- The configurations typically follow the order of filling based on the Aufbau principle.

2. **Maximum Electrons in Subshells**:
- **s subshell**:
- Contains 1 orbital.
- Maximum electrons = 2 (1 orbital × 2 electrons/orbital).
- **p subshell**:
- Contains 3 orbitals (px, py, pz).
- Maximum electrons = 6 (3 orbitals × 2 electrons/orbital).
- **d subshell**:
- Contains 5 orbitals.
- Maximum electrons = 10 (5 orbitals × 2 electrons/orbital).
- **f subshell**:
- Contains 7 orbitals.
- Maximum electrons = 14 (7 orbitals × 2 electrons/orbital).

3. **Analyzing the Given Configurations**:
- Let's evaluate the configurations:
- **1s²**: Possible (2 electrons in s subshell).
- **2p⁶**: Possible (6 electrons in p subshell).
- **3s²**: Possible (2 electrons in s subshell).
- **2p⁷**: Not possible (p subshell can only hold a maximum of 6 electrons).

4. **Conclusion**:
- The configuration **2p⁷** is not possible because the p subshell can only accommodate a maximum of 6 electrons.

### Final Answer:
The electronic configuration that is not possible is **2p⁷**.

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