Which orbit would be the first to have 'h' subshell :-

Options

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

Answer

To determine which orbit would be the first to have the 'h' subshell, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Quantum Numbers**:
- The azimuthal quantum number (l) determines the shape of the orbital and the type of subshell. The values of l are associated with different subshells as follows:
- l = 0 corresponds to s subshell
- l = 1 corresponds to p subshell
- l = 2 corresponds to d subshell
- l = 3 corresponds to f subshell
- l = 4 corresponds to g subshell
- l = 5 corresponds to h subshell

2. **Determine the Value of l for 'h' subshell**:
- Since 'h' subshell corresponds to l = 5, we need to find the principal quantum number (n) that allows for this value of l.

3. **Identify the Principal Quantum Number (n)**:
- The value of l can range from 0 to (n-1). Therefore, for l = 5, the minimum value of n must be:
\[ n - 1 \geq 5 \implies n \geq 6 \]
- This means that the first orbit where we can have an 'h' subshell is when n = 6.

4. **Conclusion**:
- The first orbit that can accommodate the 'h' subshell is the 6th orbit.

### Final Answer:
The first orbit to have an 'h' subshell is the **6th orbit**.