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	Calcium	${}_{20}{}^{40}\mathrm{Ca}$	___	____	___	____	____

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 the symbol ${}_{20}{}^{40}\mathrm{Ca}$,from that atomic number = 20

Atomic number = number of protons = number of electrons

Therefore number of proton = number of number of electron = 20

Mass number = 40

Mass number = number of protons + number of neutrons.

Therefore number of neutrons =20

Sl. No	Name of the element	Symbol	Mass number	Atomic number	Number of protons	Number of electrons	Number of neutrons
1	Calcium	${}_{20}{}^{40}\mathrm{Ca}$	40	20	20	20	20