Which orbit would be the first to have `g` subshell :-

Options

A. `3^(rd)`
B. `4^(th)`
C. `5^(th)`
D. `6^(th)`

Explanation

To determine which orbit would be the first to have a `g` subshell, we need to analyze 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.
- The azimuthal quantum number (l) determines the shape of the orbital and can take values from 0 to (n-1).

2. **Identifying Subshells**:
- Each value of l corresponds to a specific subshell:
- l = 0 corresponds to the `s` subshell
- l = 1 corresponds to the `p` subshell
- l = 2 corresponds to the `d` subshell
- l = 3 corresponds to the `f` subshell
- l = 4 corresponds to the `g` subshell

3. **Calculating l for Different n Values**:
- For n = 3:
- l can be 0, 1, or 2 (subshells: s, p, d)
- No `g` subshell present.
- For n = 4:
- l can be 0, 1, 2, or 3 (subshells: s, p, d, f)
- No `g` subshell present.
- For n = 5:
- l can be 0, 1, 2, 3, or 4 (subshells: s, p, d, f, g)
- The `g` subshell is present here.

4. **Conclusion**:
- The first orbit to have a `g` subshell is when n = 5.

### Final Answer:
The first orbit to have a `g` subshell is the **5th orbit**.

---