Two elements X and Y combine to form a compound XY. Under what conditions the bond formed between them will be ionic ?

Options

A. If the difference in electronegativities of X and Y is 1.7.
B. If the difference in electronegativities of X and Y is more than 1.7.
C. If the difference in electronegativities of X and Y is less than 1.7.
D. If both X and Y are highly electronegative.

Explanation

To determine the conditions under which the bond formed between two elements X and Y will be ionic, we can follow these steps:

### 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. This typically occurs between metals and non-metals.

2. **Electronegativity**: Electronegativity is a measure of an atom's ability to attract and hold onto electrons. The greater the difference in electronegativity between two atoms, the more likely they are to form an ionic bond.

3. **Electronegativity Difference**: For a bond to be classified as ionic, the difference in electronegativity between the two elements (X and Y) must be significant. A commonly accepted threshold is that the difference should be greater than 1.7.

4. **Conditions for Ionic Bond Formation**:
- **Metal and Non-Metal Combination**: Typically, ionic bonds form between metals (which have low electronegativity) and non-metals (which have high electronegativity).
- **Electronegativity Difference Greater than 1.7**: If the difference in electronegativity between X and Y is more than 1.7, then they are likely to form an ionic bond.

5. **Conclusion**: Therefore, the bond between elements X and Y will be ionic if the difference in their electronegativities is greater than 1.7.

### Final Answer:
The bond formed between elements X and Y will be ionic when the difference in their electronegativities is greater than 1.7.