When does radioactive decay occur? question 4 options: when neutrons accumulate in the nucleus when the nucleus decays when an atom loses electrons when an atom gains electrons?

Ans : Radioactive decay (also known as nuclear decay or radioactivity) is the process by which an unstable atomic nucleus loses energy (in terms of mass in its rest frame) by emitting radiation, such as an alpha particle, beta particle with neutrino or only a neutrino in the case of electron capture, gamma ray, or electron. The incidence occur when the nucleus of an atom possesses either too many or too few neutrons compared to the number of protons it becomes unstable. These are called radioactive isotopes. Unstable nuclei split up in a process called radioactive decay and emit radioactive radiation. You need to know the effect of alpha and beta decay on the nucleus. The nucleus of an atom can be represented as: Where: A = atomic mass (number of protons + neutrons) Z = atomic number (number of protons) X = chemical symbol (as shown on the Periodic Table) Alpha (α) decay When an alpha particle is emitted from a nucleus the nucleus loses two protons and two neutrons. This means the atomic mass number decreases by 4 and the atomic number decreases by 2. A new element is formed that is two places lower in the Periodic Table than the original element. Example: Radon decays into polonium when it emits an alpha particle. Here is the equation for that radioactive decay: Beta (β-) decay In Beta (β-) decay, a neutron changes into a proton plus an electron. The proton stays in the nucleus and the electron leaves the atom with high energy, and we call it a beta particle. When a beta particle is emitted from the nucleus the nucleus has one more proton and one less neutron. This means the atomic mass number remains unchanged and the atomic number increases by 1. Example: Carbon-14 is a radioactive isotope of carbon. (It's a carbon atom with 8 neutrons instead of the usual 6.) Here is the equation for the beta decay of carbon-14 into nitrogen.