Which one pair of atoms or ions will have same configuration ?

Options

A. `F^(o+)` and `Ne`
B. `Li^(o+)` and `He^(ɵ)`
C. `Na` and `K`
D. `Cl^(ɵ)` and `Ar`

Explanation

To determine which pair of atoms or ions have the same electronic configuration, we need to identify the number of electrons in each species and check if they match. The species that have the same number of electrons are referred to as isoelectronic species.

### Step-by-Step Solution:

1. **Identify the Species in Each Option:**
- Option 1: F⁺ and Ne
- Option 2: Li⁺ and He⁻
- Option 3: Na and K
- Option 4: Cl⁻ and Ar

2. **Calculate the Number of Electrons for Each Species:**
- **Option 1: F⁺**
- Atomic number of Fluorine (F) = 9
- F⁺ has 9 - 1 = 8 electrons.
- **Neon (Ne)**
- Atomic number of Neon = 10
- Ne has 10 electrons.
- **Conclusion for Option 1:** F⁺ (8 electrons) and Ne (10 electrons) are not isoelectronic.

3. **Option 2: Li⁺ and He⁻**
- **Li⁺**
- Atomic number of Lithium (Li) = 3
- Li⁺ has 3 - 1 = 2 electrons.
- **He⁻**
- Atomic number of Helium (He) = 2
- He⁻ has 2 + 1 = 3 electrons.
- **Conclusion for Option 2:** Li⁺ (2 electrons) and He⁻ (3 electrons) are not isoelectronic.

4. **Option 3: Na and K**
- **Na (Sodium)**
- Atomic number of Sodium = 11
- Na has 11 electrons.
- **K (Potassium)**
- Atomic number of Potassium = 19
- K has 19 electrons.
- **Conclusion for Option 3:** Na (11 electrons) and K (19 electrons) are not isoelectronic.

5. **Option 4: Cl⁻ and Ar**
- **Cl⁻ (Chlorine)**
- Atomic number of Chlorine = 17
- Cl⁻ has 17 + 1 = 18 electrons.
- **Ar (Argon)**
- Atomic number of Argon = 18
- Ar has 18 electrons.
- **Conclusion for Option 4:** Cl⁻ (18 electrons) and Ar (18 electrons) are isoelectronic.

6. **Final Answer:**
- The pair of atoms or ions that have the same electronic configuration is **Cl⁻ and Ar**.