Q. The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is
A) 2
B) 17
C) 37
D) 38
Explanation
(d)
The mass number =atomic number + number of neutron
Atomic number=no. of proton
=no. of electron (for an atom)
So, mass number =18+20=38
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.