Question

The total number of nucleons in the atoms of Calcium and Argon is 40 and the atomic numbers of Calcium and Argon are 20 and 18 respectively.

Name the pair of these two elements and also find out the number of neutrons present in the nucleus of argon atom.

Answer 1

Part 1: Identifying the name of pairs

Isobars: Isobars are those elements that have the same mass number but different atomic numbers.

Given,

Element	Atomic number	Mass Number
Argon(Ar)	18	40
Calcium(Ca)	20	40

So, Calcium and Argon are isobars because they have the same mass number and different atomic numbers.

Part 2: Calculating the number of neutrons

Number of neutrons = Mass number - Atomic number

For Calcium,

Number of neutrons = 40 - 20 = 20

For Argon,

Number of neutrons = 40 - 18 = 22