Question

Which of the following exists as molecules?

(i) Nitrogen gas

(ii) Helium

(iii) Water

• A. (ii) and (iii)
• B. (ii) only
• C. (i) and (iii)
• D. (i), (ii), and (iii)

Answer 1

The correct option is D (i), (ii), and (iii)

A molecule is the smallest particle of matter that is capable of independent existence​.
Nitrogen gas ($N_2$) is a molecule consisting of 2 nitrogen atoms. Helium (He) is a monoatomic molecule and exists independently. Water ($H_{2}O$) consists of molecule made up of 1 atom of oxygen and 2 atoms of hydrogen.