When a nucleus undergoes gamma decay, what happens to its atomic number?

1 Answer
Jun 13, 2018

Nothing. Gamma ray photons have no nonrelativistic mass.

An example of gamma decay is:

#""_(28)^(60) "Ni"^"*" -> ""_(28)^(60) "Ni" + overbrace(""_(0)^(0) gamma + "1.33 MeV")^"Energy only, no mass"#

where #""_(0)^(0) gamma# is a gamma ray photon, i.e. a nonrelativistically massless particle of light.