Beta Minus decay emits an electron or beta particle
Beta particles are electrons or positrons (electrons with positive electric charge, or anti–electrons).
Beta decay occurs when, in a nucleus with too many protons or too many neutrons, one of the protons or neutrons
is transformed into the other. In beta minus decay, a neutron decays into a proton, an electron, and an anti-neutrino:
n → p + e− + 
In beta plus decay, a proton decays into a neutron, a positron, and a neutrino:
p → n + e+ + ν
Both reactions occur because in different regions of the Chart of the Nuclides, one or the other will move the product closer
to the region of stability. These particular reactions take place because conservation laws are obeyed.
Beta Plus decay emits a positron or (beta+) particle
Inside the Nucleus the Proton can be changed to a neutron with the beta decay. In beta decay the change in binding energy appears as the mass energy and kinetic energy of the beta particle, the energy of the neutrino, and the kinetic energy of the recoiling daughter nucleus. The energy of an emitted beta particle from a particular decay can take on a range of values because the energy can be shared in many ways among the three particles while still obeying energy and momentum conservation.
Electric charge conservation requires that if an electrically neutral neutron becomes a positively charged proton, an electrically negative particle (in this case, an electron) must also be produced. Similarly, conservation of lepton number requires that if a neutron (lepton number = 0) decays into a proton (lepton number = 0) and an electron (lepton number = 1), a particle with a lepton number of −1 (in this case an antineutrino) must also be produced. The leptons emitted in beta decay did not exist in the nucleus before the decay–they are created at the instant of the decay.