Question

. Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have

Answer 1

Hi

no of proton : 2

atomic mass of helium :4

No of neutrons : ????

we know that ,
Atomic mass of atom = no of protons + no. of neutrons

we have to find no. of neutrons

therefore, 4u = 2 + no. of neutrons

4- 2 = no. of neutrons

no. of neutrons : 2

therefore, no of neutrons in helium atom: 2

May it is helpful for you .

Answer 2

☆$\red {HELLO\:DEAR}$☆

Helium atom has two neutrons.

The mass of an atom is the sum of the masses of protons and neutrons present in its nucleus.

Since helium atom has two protons, mass contributed by the two protons is (2 × 1) u = 2 u.

Then, the remaining mass (4 − 2) u = 2 u is contributed by 2u/1u = 2 neutrons.

☆$\green {VISHU\:PANDAT}$☆

☆$\blue {FOLLOW\:ME}$☆