1. Write a balanced equation for the: a. alpha decay of lead-210

b. beta decay of chromium-55

c. capture of an electron by bromine-76

210 82Pb> 206 80Hg + 4 2 He

55 24 Cr>55 25 Mn + 0 -1 e

76 35 Br + 0 -1 e> 76 34 Se

Explanation:

Alpha decay occurs with atoms having high atomic number number. As the atomic number increases, the repulsions between the protons make the nucleus unstable. A point is reached where the attractive forces in the nucleus are unable to hold the nucleons together anymore. Part of the nucleus now breaks off as an alpha particle or a helium nucleus.

Beta decay involves the transformation of a neutron to a proton, electron and neutrino. It decreases the neutron-proton ratio.

The capture of an orbital electron converts a proton into a neutron with the emission of a neutrino. The atomic number of the product nucleus decreases. Orbital electron capture increases the neutron-proton ratio.