The sum of the masses of protons and neutrons in an atom’s nucleus determines its mass.
Helium has an atomic mass of 4 and has 2 protons.
Because atomic mass equals the sum of protons and neutrons,
Atomic mass – number of protons = number of neutrons
=4-2=2
As a result, the Helium atom contains two neutrons.
Final Answer:-
Hence, the Helium atom has 2 neutrons.