Least ionic character is found in

Options

A. Mg
B. Sr
C. Ca
D. Ra

Explanation

To determine which element has the least ionic character among magnesium, calcium, strontium, and radium, we can follow these steps:

### Step 1: Identify the Group
All the elements in the question belong to Group 2 of the periodic table, which are the alkaline earth metals.

### Step 2: Understand Ionic and Covalent Character
Ionic character refers to the extent to which a bond between two atoms has ionic characteristics. Covalent character refers to the extent to which a bond has covalent characteristics. According to Fajans' rule, the covalent character increases when:
- The cation is small and has a high charge.
- The anion is large.

Conversely, if the covalent character is high, the ionic character will be low.

### Step 3: Analyze the Size of Ions
As we move down the group from magnesium (Mg) to radium (Ra), the size of the cations increases:
- Magnesium (Mg) < Calcium (Ca) < Strontium (Sr) < Radium (Ra)

### Step 4: Apply Fajans' Rule
- Magnesium has the smallest ionic size, which means it has a higher charge density.
- Radium has the largest ionic size, leading to a lower charge density.

Since smaller cations (like Mg) have a higher tendency to polarize the electron cloud of larger anions, magnesium will have more covalent character compared to the others, leading to less ionic character.

### Step 5: Conclusion
Based on the analysis, magnesium (Mg) has the least ionic character among the given options.

### Final Answer
**Magnesium (Mg)** has the least ionic character.

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