Question

Helium atoms has an atomic mass of 4u and 2 protons in its nucles . How many neutrons does it have

Answer 1

Hi dear !!!

mass number of Helium is 4u

so mass number = number of proton + number of neutron

4 = 2 + n

n = 2

hope it helps you dear

$thanks$

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.

☆$\green {VISHU\:PANDAT}$☆

☆$\blue {FOLLOW\:ME}$☆