Question

Smallest particle of an element or a compound which is capable of independent existence is called:
A. atom
B. molecule
C. element
D. compound

Answer 1

Element is a pure substance which consists of atoms having the same number of protons i.e. positively charged ions in the atomic nuclei. Elements can-not be further broken down into simpler substances by chemical changes.

Complete answer:
In an element the number of protons in the nucleus defines the property of an element which is referred to as its atomic number represented by the symbol Z and all atoms have the same atomic number are atoms of the same element.
Smallest particle of an element or compound capable of independent existence is called a molecule. A molecule is formed when two or more atoms join together where an atom consisting of nucleus in which positively charged proton and neutron which carries no charge are present and surrounded by electrons that are negatively charged. Number of protons and neutrons are always equal in an atom so that the overall charge will be neutral on an atom. Molecules of elements lie noble gases i.e. helium, neon, argon are made up of one atom only.
Hence we can say that molecules are capable of having independent existence whereas atoms do not exist independently.

Therefore, Option (B) is the correct answer.

Note: Molecule is neutral in nature having group of two or more atoms held together by chemical bonds. Molecule may be homonuclear i.e. consists of only one type of chemical element and heteronuclear consists of different types of element.