<P> Although alpha , beta , and gamma radiations were most commonly found , other types of emission were eventually discovered . Shortly after the discovery of the positron in cosmic ray products , it was realized that the same process that operates in classical beta decay can also produce positrons ( positron emission ) , along with neutrinos ( classical beta decay produces antineutrinos ) . In a more common analogous process , called electron capture , some proton - rich nuclides were found to capture their own atomic electrons instead of emitting positrons , and subsequently these nuclides emit only a neutrino and a gamma ray from the excited nucleus ( and often also Auger electrons and characteristic X-rays , as a result of the re-ordering of electrons to fill the place of the missing captured electron ) . These types of decay involve the nuclear capture of electrons or emission of electrons or positrons , and thus acts to move a nucleus toward the ratio of neutrons to protons that has the least energy for a given total number of nucleons . This consequently produces a more stable ( lower energy ) nucleus . </P>
<P> Although alpha , beta , and gamma radiations were most commonly found , other types of emission were eventually discovered . Shortly after the discovery of the positron in cosmic ray products , it was realized that the same process that operates in classical beta decay can also produce positrons ( positron emission ) , along with neutrinos ( classical beta decay produces antineutrinos ) . In a more common analogous process , called electron capture , some proton - rich nuclides were found to capture their own atomic electrons instead of emitting positrons , and subsequently these nuclides emit only a neutrino and a gamma ray from the excited nucleus ( and often also Auger electrons and characteristic X-rays , as a result of the re-ordering of electrons to fill the place of the missing captured electron ) . These types of decay involve the nuclear capture of electrons or emission of electrons or positrons , and thus acts to move a nucleus toward the ratio of neutrons to protons that has the least energy for a given total number of nucleons . This consequently produces a more stable ( lower energy ) nucleus . </P>
why do some atoms decay and emit radioactive rays
why do some atoms decay and emit radioactive rays
to move a nucleus toward the ratio of neutrons to protons that has the least energy for a given total number of nucleons
to move a nucleus toward the ratio of neutrons to protons that has the least energy for a given total number of nucleons