Question

What is the atomicity of the following ? (a) Oxygen (b) Ozone (c) Neon (d) Sulphur (e) Phosphorus (f) Sodium

Answer 1

Hint: An atom is a particle of matter that uniquely defines a chemical element. An atom consists of a central nucleus that is usually surrounded by one or more electrons. Each electron is negatively charged. The nucleus is positively charged, and contains one or more relatively heavy particles known as protons and neutrons.A proton is positively charged. The number of protons in the nucleus of an atom is the atomic number for the chemical element . A neutron is electrically neutral .

Complete answer:
Atomicity is defined as the total number of atoms present in a molecule. For example, each molecule of oxygen ( $O_2$ ) is composed of two oxygen atoms. So the atomicity of oxygen is 2. In older contexts, the term atomicity is sometimes used in the same sense as valency. On the basis of atomicity, molecules can be classified as: Monatomic – composed of 1 atom e.g $He,Ne,Ar$ (all noble gases are monatomic) Diatomic – composed of 2 atoms e.g $H_2,N_2,O_2$ Triatomic – composed of 3 atoms e.g. O3 Polyatomic – composed of 3 or more atoms e.g $.P_4,S_8$ There is a simple way to determine the atomicity of any element. It can be determined as a ratio of molecular mass and atomic mass. For example, using the case of Oxygen molecule, the molecular mass is $32\left(=2x16\right)$ while the atomic mass is $16$ . If we divide the two, we get atomicity as $2\left(=32/16\right).$ Ozone molecule, the molecular mass is $48\left(=3x16\right)$ while the atomic mass is $16$ . If we divide the two, we get atomicity as $3\left(=48/16\right).$ Neon molecule, the molecular mass is $32\left(=2x16\right)$ while the atomic mass is $16$ . If we divide the two, we get atomicity as $2\left(=32/16\right).$ Sulphur molecule, the molecular mass is $256\left(=8x32\right)$ while the atomic mass is $32$ . If we divide the two, we get atomicity as $8\left(=256/32\right).$ Phosphorus molecule, the molecular mass is $120\left(=4x30\right)$ while the atomic mass is $30$ . If we divide the two, we get atomicity as $4\left(=120/30\right).$ Sodium molecule, the molecular mass is $11\left(=1x11\right)$ while the atomic mass is $11$ . If we divide the two, we get atomicity as $1\left(=11/11\right).$

Note :
Atomicity is defined as the total number of atoms present in a molecule. There is a simple way to determine the atomicity of any element. It can be determined as a ratio of molecular mass and atomic mass.