The atomic number of element having pseudo inert gas configuration in it's atomic state is

Options

A. 46
B. 45
C. 47
D. 48

Answer

To determine the atomic number of the element that has a pseudo inert gas configuration, we need to understand what pseudo inert gas configuration means and then analyze the given options.

### Step-by-Step Solution:

1. **Understanding Pseudo Inert Gas Configuration**:
- Pseudo inert gas configuration refers to an electron configuration where the outermost shell (n) has a filled s subshell and the n-1 shell has 18 electrons instead of the typical 8 found in noble gases.
- This means that the configuration will have a complete d subshell (10 electrons) and a complete p subshell (6 electrons) in the n-1 shell, along with 2 electrons in the s subshell of the current shell.

2. **Identifying the Configuration**:
- The general form of pseudo inert gas configuration can be represented as:
- [noble gas] ns² (where n is the principal quantum number of the outermost shell)
- (n-1)d¹⁰ (completely filled d subshell)
- (n-1)p⁶ (completely filled p subshell)
- The n-1 shell must contain a total of 18 electrons.

3. **Evaluating the Given Atomic Number (46)**:
- The atomic number 46 corresponds to the element Palladium (Pd).
- Let's write the electron configuration for Palladium:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰
- Now, we check the n (5th shell) and n-1 (4th shell) configurations:
- The 5th shell has 1 electron in 5s (5s¹).
- The 4th shell has:
- 4s² (2 electrons)
- 4p⁶ (6 electrons)
- 4d¹⁰ (10 electrons)
- Total in the 4th shell = 2 + 6 + 10 = 18 electrons.

4. **Conclusion**:
- Since Palladium (atomic number 46) has a pseudo inert gas configuration with 18 electrons in its n-1 shell, the answer to the question is:
- **The atomic number of the element having pseudo inert gas configuration is 46.**