(iv) A nucleus of an atom consists of 146 neutrons and 95 protons. It decays after emitting an alpha particle. How many protons and neutrons are left in the nucleus after an alpha emission?

(a) protons = 93, neutrons = 144
(b) protons = 95, neutrons = 142
(c) protons = 89, neutrons = 144
(d) protons = 89, neutrons = 142

Solution