The covalent alkaline earth metal halide ` ( X = Cl, Br, I )` is :

Options

A. `MgX _ 2 `
B. ` Ca X _ 2 `
C. `Sr X _ 2 `
D. `BeX _ 2 `

Explanation

To determine which of the given alkaline earth metal halides (MgX2, CaX2, SrX2, and BeX2) is covalent, we can use Fajan's rule, which helps us predict the nature of the bond (covalent or ionic) based on the size and charge of the ions involved.

### Step-by-Step Solution:

1. **Understanding Fajan's Rule**:
- Fajan's rule states that the nature of the bond (ionic or covalent) can be predicted based on the charge and size of the cations and anions.
- A compound with a small cation and a large anion tends to have covalent character, while a compound with a large cation and a small anion tends to have ionic character.

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