Question

An isotope of uranium is ₉₂Y²³⁸, i.e., it has mass number 235 and atomic number 92.
Find the number of protons and neutrons in its nucleus.

Answer 1

Atomic mass = Number of protons + Number of neutrons

or 235 = 92 + Number of neutrons

∴ Number of neutrons = 235 - 92 = 143