Which will from stronger ionic bond ?
(i) Na and F (ii) Na and Cl.

Answer

To determine which pair forms a stronger ionic bond between sodium (Na) and fluorine (F) or sodium (Na) and chlorine (Cl), we need to analyze the properties of these elements, particularly their electronegativities and the nature of the ionic bond.

### Step-by-Step Solution:

1. **Understanding Ionic Bonds**:
- Ionic bonds are formed when one atom donates an electron to another atom, resulting in the formation of positively and negatively charged ions. The strength of the ionic bond is influenced by the charge of the ions and the distance between them.

2. **Identifying the Elements**:
- We have two pairs to consider:
- Pair 1: Sodium (Na) and Fluorine (F)
- Pair 2: Sodium (Na) and Chlorine (Cl)

3. **Electronegativity Values**:
- Electronegativity is a measure of an atom's ability to attract and hold onto electrons.
- Sodium (Na) has an electronegativity of about 0.93.
- Fluorine (F) has a high electronegativity of about 3.98.
- Chlorine (Cl) has an electronegativity of about 3.16.

4. **Calculating Electronegativity Differences**:
- For Na and F:
- Difference = 3.98 (F) - 0.93 (Na) = 3.05
- For Na and Cl:
- Difference = 3.16 (Cl) - 0.93 (Na) = 2.23

5. **Analyzing the Results**:
- A greater difference in electronegativity indicates a stronger ionic bond because it suggests a more significant transfer of electrons from the less electronegative atom (Na) to the more electronegative atom (F or Cl).
- The difference between Na and F (3.05) is greater than that between Na and Cl (2.23).

6. **Conclusion**:
- Since the electronegativity difference is greater for sodium and fluorine, the ionic bond formed between sodium and fluorine (NaF) will be stronger than that formed between sodium and chlorine (NaCl).

### Final Answer:
The stronger ionic bond is formed between Sodium (Na) and Fluorine (F).

---