Which of the following is most polarised among noble gases ?

Options

A. `He`
B. `Xe`
C. `Kr`
D. `Rn`

Explanation

To determine which noble gas is the most polarized among the options given, we can follow these steps:

### Step 1: Understand Polarizability
Polarizability refers to the ability of an electron cloud around an atom or molecule to be distorted by an external electric field. The more easily the electron cloud can be distorted, the more polarizable the atom or molecule is.

### Step 2: Identify the Noble Gases
The noble gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

### Step 3: Consider Atomic Size and Electron Count
Polarizability generally increases with the size of the atom and the number of electrons. Larger atoms have more diffuse electron clouds that can be distorted more easily.

### Step 4: Compare the Noble Gases
Among the noble gases:
- **Helium** has the smallest atomic size and the least number of electrons.
- **Neon** is larger than helium but still small compared to the others.
- **Argon** is larger than neon.
- **Krypton** is larger than argon.
- **Xenon** is larger than krypton.
- **Radon** is the largest noble gas and has the highest atomic number (86).

### Step 5: Conclusion
Since radon has the largest atomic size and the most electrons, it is the most polarizable noble gas. Therefore, the answer is radon.

### Final Answer
**Radon (Rn) is the most polarized among noble gases.**

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