Question

Which one of the following noble gases is the least polarizable
A. Xe
B. Ar
C. Ne
D. He

Answer 1

Hint: Helium, Neon, Argon, and Xenon are all noble gases that are generally highly unreactive except when under harsh conditions. The atomic radius of noble gases increases down the group due to the increasing electrons.

Complete Step by Step Solution:
Noble gases or inert gases form a class of chemical elements with identical properties and under standard conditions, these are odourless, colourless, monatomic gases with very insufficient chemical reactivity. These are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive gas radon (Rn).

Atomic size increases the group as the valence electrons in the larger noble gases are distant from the nucleus and are thus not held tightly together by the atom. Noble gases maintain the largest ionisation potential among the elements of each period, due to the stability of their electron configuration and thus their lack of chemical reactivity.

Here in this question, we have to find out which of the following noble gases is the least polarizable. Polarizability is a criterion that defines how readily an electron cloud is deformed by an electric field. The electric field could be induced by an electrode or a cation or an anion. If an electron cloud can be distorted it is polarizable.

Among the given options, Helium cannot be distorted easily as it possesses the smallest size. The electrons are strongly held with the nucleus. The incoming cation or anion will not be able to distort the electron cloud.
So, option D is correct.

Note: Noble gases maintain very low boiling and melting points, which makes them beneficial as cryogenic refrigerants. Liquid helium is utilised for superconducting magnets, such as those required in nuclear magnetic resonance imaging and nuclear magnetic resonance. Liquid neon is also used in cryogenics.