Question

The valency of group $16$ elements is;
A. $6$
B. $4$
C. $1$
D. $2$

Answer 1

In order to solve this question we must know what we mean by valency. The combining capacity of an atom is called its valency. The number of bonds that an atom can form as part of a compound is expressed by the valency of that element. Valence electrons are those electrons which are present in the outermost orbit of the atom.

Complete step by step answer:
The group $16$ elements of modern periodic table consist of five elements namely oxygen, sulphur, selenium, tellurium and polonium. The group $16$ elements belong to the p-block of the periodic table because their last electron enters into the p-orbital. The elements in this group are also known as the ore-forming elements or the chalcogens because many elements can be extracted from the sulphide or oxide ores.
The general electronic configuration of this group elements is $n{s^2}n{p^4}$. So the number of valence electrons present in group sixteen elements is $6$ which means that two more electrons are required to achieve the stable octet state. So the valency could be from two to six, except for Oxygen. Because oxygen does not have a d-orbital to occupy more than two electrons. Hence, the common valency of this group is 2.

So, the correct answer is Option D.

Note: Valency is different from the oxidation number because valency has no sign. Hence, the valency of nitrogen is $3$, whereas it can have oxidation numbers from $- 3$ to $+ 5$. The oxidation number is said to be the hypothetical charge of an atom in a molecule or ion, and it is a measure of its apparent capacity to gain or lose electrons within that species.