Q. 45.0( 1 Vote )

An atom has an atomic mass of 7u. It has 2 electrons in K-shell and one electron in L-shell. How many neutrons does it have?

Answer :

Atomic mass of atom = 7u

Electrons in K shell = 2


Electrons in L shell = 1


Total electrons = 2 + 1 = 3


Total protons = 3


The no. of electrons and proton and neutrons in any neutral atom are equal.


Total neutrons = atomic mass – protons


= 7 – 3 = 4


Atom has 4 neutrons.


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