Which of the following substances has the least ionic character ?

Options

A. `FeCl_2`
B. `ZnCl_2`
C. `CdCl_2`
D. `MgCl_2`

Explanation

To determine which of the given substances has the least ionic character, we will analyze the ionic character of each substance based on the nature of the elements involved and their electronegativity.

### Step-by-Step Solution:

1. **Identify the Substances**: The substances given are FeCl2, ZnCl2, CdCl2, and MgCl2.

2. **Understand Ionic Character**: Ionic character in a compound is influenced by the difference in electronegativity between the two atoms involved in the bond. A larger difference typically indicates higher ionic character.

3. **Electronegativity Consideration**:
- **FeCl2**: Iron (Fe) is a transition metal and has a moderate electronegativity.
- **ZnCl2**: Zinc (Zn) is also a transition metal but is less electropositive compared to others, which means it has a lower tendency to lose electrons and form cations.
- **CdCl2**: Cadmium (Cd) is similar to zinc but is generally more electropositive than zinc.
- **MgCl2**: Magnesium (Mg) is an alkaline earth metal and is quite electropositive, leading to a higher ionic character.

4. **Comparison of Ionic Character**:
- Since Zn is less electropositive, ZnCl2 will have less ionic character compared to the other compounds. This is because it does not form cations as readily as the others, leading to a more covalent character in its bonding.
- FeCl2, CdCl2, and MgCl2 will have higher ionic character due to the greater electropositivity of Fe, Cd, and Mg.

5. **Conclusion**: Based on the analysis, ZnCl2 has the least ionic character among the given substances.

### Final Answer:
The substance with the least ionic character is **ZnCl2**.

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