Solution:
Monoatomic has more than one type of atom but atomicity 2 is an incorrect statement regarding atomicity.All matter is made up of particles. The smallest particle of matter is an atom. The radius of an atom is less than 1nm. Atoms combine to form molecules such as P4, H2O, N2, S8, and O3. Atomicity is the number of atoms constituting a molecule and compound. Atomicity of P4, H2O, N2, S8, and O3 is 4, 3,2,8, and 3 respectively.
Argon is monatomic and its atomicity is 1 but the polyatomic has an atomicity of more than 4. O2 is diatomic as its atoms are two.
