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 atomic number, electronic configuration, block, and period.

### Step-by-Step Solution:

1. **Option 1: Element with Atomic Number 89 (Actinium)**
- **Identify the Element**: The element with atomic number 89 is Actinium (Ac).
- **Electronic Configuration**: The electronic configuration of Actinium is:
\[ \text{1s}^2 \text{2s}^2 \text{2p}^6 \text{3s}^2 \text{3p}^6 \text{4s}^2 \text{3d}^{10} \text{4p}^6 \text{5s}^2 \text{4d}^{10} \text{5p}^6 \text{6s}^2 \text{4f}^{14} \text{5d}^{10} \text{6p}^6 \text{7s}^2 \text{5f}^{2} \]
- **Determine Block and Period**: The last electron enters the 6d subshell, indicating that Actinium is a **d-block element** and belongs to the **7th period**.
- **Mismatch Check**: The option states it is a 6th period element, which is incorrect. Thus, **Option 1 is mismatched**.

2. **Option 2: Element with Atomic Number 100 (Fermium)**
- **Identify the Element**: The element with atomic number 100 is Fermium (Fm).
- **Electronic Configuration**: The electronic configuration of Fermium is:
\[ \text{1s}^2 \text{2s}^2 \text{2p}^6 \text{3s}^2 \text{3p}^6 \text{4s}^2 \text{3d}^{10} \text{4p}^6 \text{5s}^2 \text{4d}^{10} \text{5p}^6 \text{6s}^2 \text{4f}^{14} \text{5d}^{10} \text{6p}^6 \text{7s}^2 \text{5f}^{12} \]
- **Determine Block and Period**: The last electron enters the 5f subshell, indicating that Fermium is an **f-block element** and belongs to the **7th period**.
- **Mismatch Check**: The option correctly identifies Fermium as an f-block element in the 7th period. Thus, **Option 2 is correct**.

3. **Option 3: Element with Atomic Number 115 (Moscovium)**
- **Identify the Element**: The element with atomic number 115 is Moscovium (Mc).
- **Electronic Configuration**: The electronic configuration of Moscovium is:
\[ \text{1s}^2 \text{2s}^2 \text{2p}^6 \text{3s}^2 \text{3p}^6 \text{4s}^2 \text{3d}^{10} \text{4p}^6 \text{5s}^2 \text{4d}^{10} \text{5p}^6 \text{6s}^2 \text{4f}^{14} \text{5d}^{10} \text{6p}^6 \text{7s}^2 \text{5f}^{14} \text{6d}^{10} \text{7p}^3 \]
- **Determine Block and Period**: The last electron enters the 7p subshell, indicating that Moscovium is a **p-block element** and belongs to the **7th period**.
- **Mismatch Check**: The option states it is a d-block element, which is incorrect. Thus, **Option 3 is mismatched**.

4. **Conclusion**:
- Both **Option 1** and **Option 3** are mismatched regarding the position of the elements. Therefore, the answer is **Option 4: Both 1 and 3**.