The emission of radiation from an unstable nucleus may cause changes to the nucleus, including:
Changes due to radioactive decay can be represented by balanced nuclear equations. The changes that happen depend on the type of radiation emitted.
Radon-219 decays into polonium-215 by emitting an alpha particle. This is the balanced equation for the reaction:
Polonium nuclei have 84 protons, so their nuclear charge is +84. They have two fewer protons than radon nuclei, which have 86 protons and so a nuclear charge of +86.
A beta particle forms when a neutron changes into a proton and a high-energy electron. The proton stays in the nucleus but the electron leaves the atom as a beta particle. When a nucleus emits a beta particle, these changes happen:
Carbon-14 decays into nitrogen-14 by emitting a beta particle. This is the balanced equation for the reaction:
Nitrogen nuclei have 7 protons, so their nuclear charge is +7. They have one more proton than carbon nuclei, which have 6 protons and so a nuclear charge of +6.
Gamma radiation transfers energy from the nucleus, so the symbol may appear in some balanced equations.