The pair of elements that would likely to form an ionic bond is

Options

A. K, Br
B. C, H
C. K, Ar
D. K, K

Explanation

To determine which pair of elements is likely to form an ionic bond, we need to analyze the electronic configurations of the elements in each pair and understand how ionic bonds are formed.

### Step-by-Step Solution:

1. **Understanding Ionic Bonds**: Ionic bonds are formed when one atom transfers electrons to another atom, resulting in the formation of positively and negatively charged ions. This typically occurs between metals and non-metals.

2. **Identify the Given Pairs**: Let's assume the pairs given in the question are:
- Pair 1: K (Potassium) and Br (Bromine)
- Pair 2: C (Carbon) and H (Hydrogen)
- Pair 3: K (Potassium) and Ar (Argon)
- Pair 4: K (Potassium) and K (Potassium)

3. **Analyze Pair 1 (K and Br)**:
- **Potassium (K)**: Electronic configuration is 2, 8, 8, 1. It has 1 valence electron.
- **Bromine (Br)**: Electronic configuration is 2, 8, 18, 7. It has 7 valence electrons.
- **Bond Formation**: K will lose 1 electron, and Br will gain 1 electron. This transfer results in K⁺ and Br⁻ ions, forming KBr, which is an ionic compound.

4. **Analyze Pair 2 (C and H)**:
- **Carbon (C)**: Electronic configuration is 2, 4. It has 4 valence electrons.
- **Hydrogen (H)**: Electronic configuration is 1. It has 1 valence electron.
- **Bond Formation**: Carbon cannot lose or gain 4 electrons easily; instead, it shares electrons with hydrogen, forming a covalent bond (CH₄). Therefore, this pair does not form an ionic bond.

5. **Analyze Pair 3 (K and Ar)**:
- **Argon (Ar)**: Electronic configuration is 2, 8, 8. It has a complete outer shell and is inert.
- **Bond Formation**: Potassium can lose 1 electron, but Argon will not gain or lose electrons. Thus, no bond is formed between K and Ar.

6. **Analyze Pair 4 (K and K)**:
- Both are Potassium atoms, which means they both have 1 valence electron.
- **Bond Formation**: There is no transfer of electrons as both would lose an electron but there is no atom to gain it. Hence, no ionic bond is formed.

7. **Conclusion**: The only pair that forms an ionic bond is K (Potassium) and Br (Bromine), resulting in the formation of KBr.

### Final Answer:
The pair of elements that would likely form an ionic bond is **K (Potassium) and Br (Bromine)**.