An atom can change into an atom of another element through nuclear reactions, which may involve radioactive decay or other changes to the atom's nucleus. This is possible in atoms with unstable nuclei and radioactive properties, where isotopes can transmute into different elements.
An atom of an element can change into an atom of another element through a process involving changes to the nucleus. This typically occurs within radioactive elements or during nuclear reactions. Unlike ordinary chemical reactions, where the identity of an atom's nucleus does not change, nuclear reactions can alter the nucleus by adding or removing protons or neutrons, effectively changing one element into another. For example, all atoms with 84 or more protons are naturally radioactive, and can transform into different elements by emitting particles such as alpha and beta particles during radioactive decay. Similarly, isotopes, which are atoms of the same element with varying numbers of neutrons, can also undergo nuclear changes that transmute them into different elements. This is consistent with Einstein's famous equation, E=mc², which allows for mass and energy conversion, underlining that in nuclear reactions, the conservation of mass and energy applies together rather than separately.