Describe the process of electron capture. What happens to the mass number and atomic number of a nuclide that undergoes electron capture?

Beta decay is a nuclear process where an unstable atom transforms into a more stable one by emitting a beta particle, which can be either an electron or a positron. This alteration involves a change in the composition of the atom's nucleus and comes in two main forms: beta-minus and beta-plus decay. In beta-minus decay, a neutron in the nucleus turns into a proton, an electron, and an anti-neutrino; the electron and anti-neutrino are shot out of the atom. Conversely, in beta-plus decay, a proton is converted into a neutron, a positron (the electron's antiparticle), and a neutrino, with the positron and neutrino being emitted.

Electron capture is a unique type of beta decay. Instead of emitting a particle, the nucleus captures an electron from the closest electron shell, typically the K-shell. This electron then merges with a proton to form a neutron and a neutrino. The neutrino escapes from the nucleus, leaving the atom with altered nuclear components but the same mass number.

Understanding beta decay is important for comprehending various phenomena, such as the changes in isotopes used for dating materials in archeology, as well as applications in medicine and energy generation.

The atomic number, represented by the symbol 'Z', is a fundamental property of an element and defines its position in the periodic table. It signifies the number of protons in the nucleus of an atom. Since each element has a unique number of protons, the atomic number also identifies the type of element. For example, carbon has an atomic number of 6 because every carbon atom contains 6 protons.

During electron capture, the atomic number of a nuclide decreases by one. This occurs because an electron from an inner shell of the atom combines with a proton in the nucleus, converting it into a neutron. The loss of a proton effectively changes the identity of the element to the one with the next lower atomic number in the periodic table. This shift is crucial because it can transform one chemical element into another, and this transmutation plays a key role in both natural processes and technological applications, such as in the synthesis of new elements.

The mass number, indicated by the symbol 'A', is the total count of protons and neutrons (together known as nucleons) found in an atom's nucleus. It provides an approximation of the atomic mass. For instance, the mass number of a carbon atom with 6 protons and 6 neutrons is 12. It's important to note that the mass number is not the same as the atomic mass, which takes into account the isotopic distribution of an element in nature and includes unit contributions from electrons.

When electron capture happens, the mass number stays the same because the proton in the nucleus is replaced by a neutron. Since the mass difference between a proton and a neutron is minimal, the overall mass of the nucleus does not significantly change. However, since neutrons have no charge, the chemical behavior of the resulting atom can be different, which is why the mass number is significant for nuclear reactions. It aids in understanding not only the stability of nuclei but also the mechanisms underlying nuclear reactions and decays.