Question

What is the sum of protons, electrons and neutrons in a stable isotope of cobalt?

• A. 86
• B. 87
• C. 88
• D. 89

Answer 1

The correct option is A

86

The explanation for the correct option

• Option(A): The stable isotope of cobalt is ${}_{27}{}^{59}\mathrm{Co}$.
• It has 27 protons and 27 electrons.
• Number of neutrons=(59-27) = 32.
• Hence the sum of protons, neutrons and electrons=(27+27+32) = 86.

Thus option(A) is the correct answer. i.e., the sum of protons, electrons and neutrons in a stable isotope of cobalt is 86.