Q. The difference between $U^{235}and\ U^{238}$ atom is that
A) $U^{238}$contains 3 more protons
B) $U^{238}$contains 3 protons and 3 more electrons
C) $U^{238}$contains 3 more neutrons and 3 more electrons
D) $U^{238}$contains 3 more neutrons
Explanation
(d) As charge number is fixed (=92), therefore, number of protons and electrons is same. As atomic weight is greater by 3, therefore $\ _{92}U^{238}\ $contains 3 more neutrons.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.