Question

The valency of noble gases is generally:
A. Zero
B. One
C. Three
D. Two

Answer 1

Hint: The valency is calculated by determining the number of electrons in the outermost shell (also called valence shell) of each atom of an element. Also, we can say that the valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules. Noble gases don't take part in chemical reactions.

Complete Step by step solution:
Noble gases are called noble gases because they are so majestic that, in general, they don't react with anything. Hence noble gases are also known as inert gases.
The following seven gases are known as noble gases.
Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), oganesson (Og).
For example, consider helium. The molecular formula for helium is $He$, atomic number is 2, and the molecular weight is 4.003 grams per mol.
Helium does not exchange or share electrons to form bonds with any other molecules. Helium has one shell (k) which requires two electrons and helium has two-electrons so the outermost shell is filled and helium has no need to lose electrons or gain electrons. Therefore the valency of helium is taken as zero.
Similarly, every noble gas consisting of its outermost shell is filled hence they don’t lose or gain any electron. Hence the valency of noble gases is zero.

According to the above information, we can conclude that the correct answer to the given question is an option(A) zero.

Note: Noble gases have eight electrons in their outermost orbit (except helium). Thus, they exhibit a stable octet configuration. But helium exhibits a duplet configuration. The general configuration of the noble gas family is given as \[n{{s}^{2}}n{{p}^{6}}~\] (except helium which has \[1{{s}^{2}}\]). So, don’t confuse between these configurations.