11mass number is 45 and atomic number is 21. so number of neutrons should be 45-21=24
An atom X is represented as follows {}_{21}^{45} ext{X}. The numbers of protons, electrons and neutrons in this atom are:
a) 21, 21, 24 b) 21,21,23 c) 20,20,24 d) 20,20,23
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3 Answers
1111Atomic no 21,mass no =45
So no of protons=21
electrons=21
nuetrons=45-21
69Atomic Number = 21
Atomic Mass = 45
Therefore, number of protons = 21
number of electrons = 21
number of neutrons = 45-21
=45-21=24