In a decay equation, which statement correctly distinguishes beta minus decay from electron capture?

In a decay equation, which statement correctly distinguishes beta minus decay from electron capture?

• A. Electron capture places a neutron on the reactant side.
• B. Beta minus decay places an electron on the product side.
• C. Beta minus decay places a neutron on the product side.
• D. Electron capture places an electron on the product side.

Answer: (B)

This question hinges on where the electron appears in the equation for each process. In beta minus decay, a neutron converts into a proton and emits an electron (and an antineutrino). That electron shows up on the product side, not the reactant side. In electron capture, a proton in the nucleus captures one of the atom’s electrons and becomes a neutron, emitting a neutrino. The captured electron is removed from the atom, so it appears on the reactant side, not the product side. Therefore, the statement that beta minus decay places an electron on the product side is the correct distinction.

This question hinges on where the electron appears in the equation for each process. In beta minus decay, a neutron converts into a proton and emits an electron (and an antineutrino). That electron shows up on the product side, not the reactant side. In electron capture, a proton in the nucleus captures one of the atom’s electrons and becomes a neutron, emitting a neutrino. The captured electron is removed from the atom, so it appears on the reactant side, not the product side. Therefore, the statement that beta minus decay places an electron on the product side is the correct distinction.