Question

Does an atom become an ion during beta and alpha decay? For example, with alpha decay, 2 protons leave, then the atom is negatively charged because of the extra electrons. Or are the electrons leaving too?

Answer 1

During alpha and beta decay, the nucleus of an atom undergoes changes, but the electronic structure (the arrangement of electrons in energy levels) remains largely unaffected. Let's examine both alpha and beta decay to understand the role of electrons in these processes:

1. Alpha Decay: In alpha decay, an alpha particle, which consists of two protons and two neutrons, is emitted from the nucleus. This emission results in the atom's atomic number decreasing by 2 and its atomic mass decreasing by 4. However, the electron configuration remains unchanged because the loss of two protons is balanced by the loss of two electrons from the atom. The atom that undergoes alpha decay becomes a different element since its atomic number changes.

2. Beta Decay: Beta decay involves the emission of beta particles, which can be either beta-minus particles (electrons) or beta-plus particles (positrons). In beta-minus decay, a neutron in the nucleus transforms into a proton, and an electron (beta particle) and an antineutrino are emitted. In this process, the atomic number increases by one, but the atomic mass remains the same. The extra electron emitted in beta-minus decay can be thought of as a new electron added to the atom, which balances the increased positive charge due to the additional proton. Similarly, in beta-plus decay, a proton transforms into a neutron, and a positron and a neutrino are emitted, resulting in a decrease of atomic number by one.

In both types of beta decay, the electron configuration of the atom changes due to the transformation of a neutron to a proton or vice versa, but the total number of electrons in the atom remains the same. The emitted electrons or positrons are not the electrons from the electron shells surrounding the atom's nucleus, but rather particles originating from the decay process within the nucleus itself.

To summarize, in alpha decay, the loss of protons is balanced by the loss of electrons, maintaining the electron configuration, while in beta decay, the electron configuration changes due to the transformation of a neutron to a proton or vice versa, but the total number of electrons in the atom remains the same.