symbolized that way— . The 4 represents the mass number, and the 2
represents the atomic number (number of protons).
To sum up alpha decay:• An alpha particle is emitted.• The atomic number decreases by 2; the mass number decreases
by 4.Radioactive Decay Type 2: Beta Decay
Sometimes a nucleus becomes more stable through beta decay, in which it
reduces its neutron-to-proton ratio by taking a neutron and turning it into a
proton. In these cases, the atomic number goes up by 1, since there’s an extra
proton, but the mass number remains the same. (It lost a neutron, but it gained a
proton, so there is no net change in the mass number.) When an atom undergoes
beta decay, it emits a beta particle; a beta particle is identical to an electron and
is symbolized as .
To sum up beta decay:• A neutron is converted to a proton.• A beta particle (an electron) is emitted.• The atomic number increases by 1, but the mass number stays
the same.