Assertion : `Cl^-` ions and `K^+` ions are isoelectronic.
Reason : Isoelectronic ions have same charge.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Answer

To solve the question, we need to analyze both the assertion and the reason provided:

### Step 1: Understand the Assertion
The assertion states that Cl⁻ ions and K⁺ ions are isoelectronic.

- **Definition of Isoelectronic**: Isoelectronic species are atoms, ions, or molecules that have the same number of electrons.

### Step 2: Determine the Number of Electrons in Cl⁻
- **Atomic Number of Chlorine (Cl)**: 17
- **Electrons in Cl**: 17 (since it is neutral)
- **Cl⁻ Ion**: This ion has gained one electron.
- Therefore, the total number of electrons in Cl⁻ = 17 + 1 = 18 electrons.

### Step 3: Determine the Number of Electrons in K⁺
- **Atomic Number of Potassium (K)**: 19
- **Electrons in K**: 19 (since it is neutral)
- **K⁺ Ion**: This ion has lost one electron.
- Therefore, the total number of electrons in K⁺ = 19 - 1 = 18 electrons.

### Step 4: Compare the Number of Electrons
- Both Cl⁻ and K⁺ have 18 electrons.
- Since they have the same number of electrons, Cl⁻ and K⁺ are indeed isoelectronic.

### Step 5: Analyze the Reason
The reason states that isoelectronic ions have the same charge.
- This statement is incorrect. Isoelectronic species have the same number of electrons, not necessarily the same charge. For example, Cl⁻ has a -1 charge, while K⁺ has a +1 charge.

### Conclusion
- **Assertion**: True (Cl⁻ and K⁺ are isoelectronic)
- **Reason**: False (Isoelectronic ions do not have to have the same charge)

### Final Answer
The correct option is that the assertion is correct, but the reason is incorrect.

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