Question

helium atom has an atomic mass of 4 u and two protons in its nucleus how many neutrons does it have​

Answer 1

Answer:

2 Neutrons in nucleus of helium

Answer 2

Answer:

number of protons in helium = 2

mass of helium = 4u

number of prothons + number of neutron = mass number

So,

    consider neutron as x

    2+x = 4

    x = 4-2

x= 2

number of neutron = 2