The subshells which are filled just before and just after the filling of 5p subshell are respectively : 

Options

A. `5s, 5d`
B. `4d, 6s`
C. `4d,4f`
D. `6s, 4f`

Answer

To determine the subshells that are filled just before and just after the filling of the 5p subshell, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Order of Filling**: Electrons fill subshells in order of increasing energy levels according to the Aufbau principle. The order of filling is typically represented by the n + l rule, where 'n' is the principal quantum number and 'l' is the azimuthal quantum number.

2. **List the Subshells**: The order of subshell filling is as follows:
- 1s
- 2s
- 2p
- 3s
- 3p
- 4s
- 3d
- 4p
- 5s
- 4d
- 5p
- 6s

3. **Identify the 5p Subshell**: The 5p subshell is filled after the 4d subshell and before the 6s subshell.

4. **Determine the Subshells Before and After 5p**:
- The subshell filled just before 5p is **4d**.
- The subshell filled just after 5p is **6s**.

5. **Conclusion**: Therefore, the subshells that are filled just before and just after the filling of the 5p subshell are **4d** and **6s**, respectively.

### Final Answer:
The subshells which are filled just before and just after the filling of the 5p subshell are **4d** and **6s**.

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