Question

Find the sum of atomicity of nitrogen and phosphorus?

Answer 1

Hint: To answer this question we must have some idea about the term Atomicity. It is defined as the total number of atoms that constitute a molecule. Now you can easily answer the question using this definition.

Complete answer:
As we already know atomicity is the total number of atoms present in one molecule of a substance. All metals and some other elements, such as carbon, do not have a simple structure but consist of a very large and indefinite number of atoms bonded together. Their atomicity cannot be determined and is usually considered as 1.
Atomicity may vary in different allotropes of the same element.
Now, we will find the atomicity of nitrogen and phosphorus.
The atomicity of nitrogen is 2 in $N_2$ molecules, as this molecule contains 2 atoms of nitrogen element.
The atomicity of phosphorus is 4 in $P_4$ molecules, as this molecule contains 4 atoms of phosphorus element..
Hence, the sum of the atomicity of nitrogen and phosphorus molecules will be,
= atomicity of nitrogen + atomicity of phosphorus = 2+4 = 6.

Therefore, the correct answer for the sum of atomicity of nitrogen and phosphorus = 6

Note: On the basis of atomicity, molecules in chemistry can be classified as,
Monoatomic - These are composed of one atom e.g. He, Ne, Ar (all noble gases are monatomic)
Diatomic - These are composed of two atoms e.g. $H_2,N_2,O_2$
Triatomic - These are composed of three atoms e.g. $N_3$
Polyatomic - These are composed of three or more atoms e.g. $P_4,S_8$