Among `LiCl, RbCl, BeCl_2, MgCl_2`, the compounds with greatest and least ionic character respectively are

Options

A. `LiCl, RbCl`
B. `RbCl, BeCl_2`
C. `RbCl, MgCl_2`
D. `MgCl_2, BeCl_2`

Explanation

To determine the compounds with the greatest and least ionic character among LiCl, RbCl, BeCl2, and MgCl2, we can follow these steps:

### Step 1: Identify the Cations and Anions
The compounds consist of the following cations and anions:
- **LiCl**: Li⁺ and Cl⁻
- **RbCl**: Rb⁺ and Cl⁻
- **BeCl₂**: Be²⁺ and Cl⁻
- **MgCl₂**: Mg²⁺ and Cl⁻

### Step 2: Understand Ionic Character
Ionic character refers to the extent to which a compound exhibits ionic bonding as opposed to covalent bonding. The ionic character is influenced by the charge and size of the cations. Higher charge density (charge/size ratio) typically leads to greater ionic character.

### Step 3: Analyze Charge Density
- **Li⁺**: Charge = +1, Radius = small
- **Rb⁺**: Charge = +1, Radius = larger than Li⁺
- **Be²⁺**: Charge = +2, Radius = small (high charge density)
- **Mg²⁺**: Charge = +2, Radius = larger than Be²⁺ (but still smaller than Li⁺ and Rb⁺)

### Step 4: Compare Charge Densities
- **Li⁺** has a relatively high charge density due to its small size.
- **Rb⁺** has the lowest charge density due to its larger size.
- **Be²⁺** has the highest charge density because it has a +2 charge and a small radius.
- **Mg²⁺** has a lower charge density than Be²⁺ but higher than Li⁺ and Rb⁺.

### Step 5: Determine Ionic Character
- **Greatest Ionic Character**: BeCl₂ (due to Be²⁺ having the highest charge density)
- **Least Ionic Character**: RbCl (due to Rb⁺ having the lowest charge density)

### Conclusion
The compounds with the greatest and least ionic character respectively are:
- **Greatest Ionic Character**: BeCl₂
- **Least Ionic Character**: RbCl

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