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, where a proton is converted into a neutron, and a positron and a neutrino are emitted. Therefore, the number of protons in the nucleus decreases by 1, and the atomic number decreases by 1. In this case, the copper isotope 11ea7811_3ad3_8839_bbd5_e9486d3df8c5_TB4511_11 has atomic number 29, and after emitting a positron, it becomes an element with atomic number 28. Looking at the choices, only option B represents an element with 28 as the atomic number: 11ea7811_3ad3_af4b_bbd5_e10713b3de46_TB4511_11, which is Ni-58.

When a Nucleus of the Copper Isotope Emits a Positron