The sub-shell `2d` is not posible because

Options

A. `n = 1`
B. `l gt n`
C. `n lt l`
D. None of these

Explanation

To determine why the sub-shell `2d` is not possible, we need to understand the relationship between the principal quantum number (n) and the azimuthal quantum number (l).

### Step-by-Step Solution:

1. **Understanding Quantum Numbers**:
- The principal quantum number (n) indicates the energy level of an electron in an atom. It can take positive integer values: 1, 2, 3, etc.
- The azimuthal quantum number (l) defines the shape of the orbital and can take values from 0 to (n-1).

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