Atomic Structure — Question 1

(a) Atom — An atom is the smallest particle of an element that exhibits all the properties of that element. It may or may not exist independently but takes part in every chemical reactions.

Example : O — Oxygen atom, H — Hydrogen atom

(b) Molecule — A molecule is the smallest particle of an element or compound, made up of two or more atoms of an element or compound which has independent existence exhibiting all of their properties.

Example : O₂ — Oxygen molecule, H₂O — Water molecule

(c) Radical — A radical is an atom of an element or a group of atoms of different elements that behaves as a single unit with a positive or negative charge on it.

Example : NH₄⁺ — Ammonium radical