With the help of the given table, find out the mass number of oxygen and sulphur atom.

Composition of Atoms of the First Eighteen Elements with Electron Distribution in Various Shells.

(a) Mass number of oxygen = ?

Given,

Number of protons = 8

Number of neutrons = 8

Mass number = Number of protons + number of neutrons = 8 + 8 = 16

∴ Mass number of oxygen = 16

(b) Mass number of Sulphur = ?

Number of protons = 16

Number of neutrons = 16

Mass number = Number of protons + number of neutrons = 16 + 16 = 32

∴ Mass number of sulphur = 32