Which of the alkali metals has the polarizing power close to that of Magnesium ?

Options

A. Lithium
B. Sodium
C. Potassium
D. Caesium

Answer

To determine which alkali metal has polarizing power close to that of magnesium, we can follow these steps:

### Step 1: Understand Polarizing Power
Polarizing power refers to the ability of a cation to distort the electron cloud of an anion. This property is influenced by the charge and size of the cation. Smaller cations with higher charges have greater polarizing power.

### Step 2: Identify the Alkali Metals
The alkali metals include:
- Lithium (Li)
- Sodium (Na)
- Potassium (K)
- Caesium (Cs)

### Step 3: Compare with Magnesium
Magnesium (Mg) is not an alkali metal but is in the same period as lithium. It has a +2 charge and a relatively small ionic radius compared to other alkali metals.

### Step 4: Recognize the Diagonal Relationship
Lithium (Li) and Magnesium (Mg) exhibit a diagonal relationship in the periodic table. This means that they share similar properties, including polarizing power, due to their comparable ionic sizes and charges.

### Step 5: Conclusion
Among the alkali metals, lithium has polarizing power that is close to that of magnesium because of their diagonal relationship in the periodic table.

### Final Answer
**Lithium (Li)** is the alkali metal with polarizing power close to that of magnesium.

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