When a radioactive isotope decays by electron capture, the electron _________.
A)combines with a neutron in the nucleus, raising the mass number of the daughter isotope by one
B)makes the daughter isotope into an ion with a charge of positive one
C)combines with a proton in the nucleus; the atomic number of the daughter is one less than the parent
D)makes the parent isotope into an ion with a charge of negative one

Question

Quizplus · Accepted Answer

Electron capture is a decay mode in which a nucleus absorbs an electron from the innermost electron shells, producing a neutron in the process. The electron combines with a proton to make a neutron, and the atomic number of the daughter is one less than the parent. The mass number remains the same. Thus, choice C is the correct answer.

When a Radioactive Isotope Decays by Electron Capture, the Electron