`X^(+), Y^(2+)` and `Z^(-)` ions are isoelectronic of `CO_(2)`. The sequence in number of protons in these ions will be

Options

A. `X^(+) = Y^(2+) =Z^(-)`
B. `X^(+) lt Y^(2+) lt Z^(-)`
C. `Z^(-) lt X^(+) lt Y^(2+)`
D. `Y^(2+) lt X^(+) lt Z^(-)`

Explanation

To solve the problem, we need to determine the number of protons in the ions \(X^{+}\), \(Y^{2+}\), and \(Z^{-}\) that are isoelectronic with carbon dioxide (\(CO_2\)).

### Step-by-Step Solution:

1. **Determine the number of electrons in \(CO_2\)**:
- Carbon (\(C\)) has an atomic number of 6, which means it has 6 electrons.
- Each oxygen (\(O\)) atom has an atomic number of 8, contributing 8 electrons each. Since there are 2 oxygen atoms:
\[ \text{Total electrons from oxygen} = 2 \times 8 = 16 \]
- Therefore, the total number of electrons in \(CO_2\) is:
\[ 6 + 16 = 22 \text{ electrons} \]

2. **Identify the number of electrons in each ion**:
- Since \(X^{+}\), \(Y^{2+}\), and \(Z^{-}\) are isoelectronic with \(CO_2\), they also have 22 electrons.

3. **Calculate the number of protons for each ion**:
- The number of protons can be calculated using the formula:
\[ \text{Number of protons} = \text{Number of electrons} + \text{Charge} \]

- For \(X^{+}\):
- Number of electrons = 22
- Charge = +1
\[ \text{Number of protons in } X^{+} = 22 + 1 = 23 \]

- For \(Y^{2+}\):
- Number of electrons = 22
- Charge = +2
\[ \text{Number of protons in } Y^{2+} = 22 + 2 = 24 \]

- For \(Z^{-}\):
- Number of electrons = 22
- Charge = -1
\[ \text{Number of protons in } Z^{-} = 22 - 1 = 21 \]

4. **Determine the sequence of the number of protons**:
- The number of protons in each ion is:
- \(Z^{-}\): 21 protons
- \(X^{+}\): 23 protons
- \(Y^{2+}\): 24 protons
- Therefore, the sequence in the number of protons is:
\[ Z^{-} < X^{+} < Y^{2+} \]

### Final Answer:
The sequence in the number of protons in the ions is:
\[ Z^{-} < X^{+} < Y^{2+} \]