Question

Helium atom has an atomic mass of 40 and two has protons
in its nuleus. How many
neutrons does it have?
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Answer 1

Answer:

2 neutron****

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.

.

. maybe

Answer 2

Answer:

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=2u.