Question

Complete the following table.

Sl. No	Name of the element	Symbol	Mass number	Atomic number	Number of protons	Number of electrons	Number of neutrons
1	Sodium	${}_{11}{}^{23}\mathrm{Na}$	___	___	11	___	___

Answer 1

Definition of atomic number.

Atomic number is defined as the number of protons present inside the nucleus of an atom.

Atomic number = number of protons = number of electrons

Definition of mass number.

Mass number is defined as the sum of number of protons and number of neutrons present inside the nucleus of an atom.

Mass number = number of protons + number of neutrons.

Given ${}_{11}{}^{23}\mathrm{Na}$ and number of proton = 11

Therefore number of electron = Atomic number =11

Mass number = 23

Therefore number of neutron = Mass number - Atomic number =12

Sl. No	Name of the element	Symbol	Mass number	Atomic number	Number of protons	Number of electrons	Number of neutrons
1	Sodium	${}_{11}{}^{23}\mathrm{Na}$	23	11	11	11	12