When a nucleus of the copper isotope emits a positron, it becomes
A) .
B) .
C) .
D) .

Question

When a nucleus of the copper isotope  emits a positron, it becomes
A) . 
B) . 
C) . 
D) .

Quizplus · Accepted Answer

When a nucleus emits a positron, it undergoes beta-plus decay. This means that a proton in the nucleus is converted into a neutron, and a positron and a neutrino are emitted. The atomic number (number of protons) decreases by one while the mass number (number of protons and neutrons) remains the same. Therefore, the best choice is B, where the atomic number decreases from 29 (copper) to 28 (nickel) while the mass number remains 71.

When a Nucleus of the Copper Isotope Emits a Positron