All atoms of an element have the same number of protons in their nuclei. Transmutation takes place when there is a change in the number of protons in a nucleus.
Transmutation occurs naturally, and it can be produced artificially.
In alpha decay, a nucleus emits an alpha particle, which consists of two protons and two neutrons. For example, the nucleus of a radium atom has 88 protons. In beta decay, a nucleus emits a beta particle. In most cases, the beta particle is an electron, a negatively charged particle. In this kind of beta decay, a neutron changes into a proton and emits the electron.