Which is mismatched regarding the position of the element as given below ?

Options

A. `X(Z=89) -f "block" , 6^(th)` period
B. Y(Z=100 ) -f block , `7^(th)` period
C. Z(Z=115) -d block , `7^(th)` period
D. Both (1) & (3)

Answer

To determine which option is mismatched regarding the position of the elements, we will analyze each option based on the given atomic numbers and their respective electronic configurations.

### Step 1: Analyze the first option (x, Z = 89)
- **Element**: Actinium (Ac)
- **Atomic Number**: 89
- **Electronic Configuration**:
- The electronic configuration of Actinium is:
\[ [Rn] 6d^1 7s^2 \]
- **Block**: f-block (as it is part of the actinide series)
- **Period**: 7th period (since the highest principal quantum number is 7)

**Conclusion**: This option is correctly matched.

### Step 2: Analyze the second option (y, Z = 100)
- **Element**: Fermium (Fm)
- **Atomic Number**: 100
- **Electronic Configuration**:
- The electronic configuration of Fermium is:
\[ [Rn] 5f^{12} 7s^2 \]
- **Block**: f-block (as it is part of the actinide series)
- **Period**: 7th period (since the highest principal quantum number is 7)

**Conclusion**: This option is correctly matched.

### Step 3: Analyze the third option (z, Z = 115)
- **Element**: Moscovium (Mc)
- **Atomic Number**: 115
- **Electronic Configuration**:
- The electronic configuration of Moscovium is:
\[ [Rn] 5f^{14} 6d^{10} 7s^2 7p^3 \]
- **Block**: p-block (as the last electron enters the p orbital)
- **Period**: 7th period (since the highest principal quantum number is 7)

**Conclusion**: This option is correctly matched.

### Final Conclusion:
Since all the options appear to be correctly matched based on their electronic configurations and positions in the periodic table, the question seems to imply that there is a mismatch. However, based on the analysis, it appears that the mismatches mentioned in the video are incorrect.

Thus, the correct answer to the question "Which is mismatched regarding the position of the element?" is that none of the options are mismatched.