Question 18.3: (a) Write an equation for the loss of an alpha particle from...

(a) Loss of an alpha particle, ^4_2He results in a decrease of 4 in the mass number and a decrease of 2 in the atomic number:

Mass of new nuclide:                        A   –   4         or        194   –  4 = 190

Atomic number of new nuclide:     Z  –   2           or        78    –  2 = 76

Looking up element number 76 on the periodic table, we find it to be osmium, Os The equation then is

^{194}_{78}Pt → ^{190}_{76}Os   +  ^4_2He

(b) The loss of a beta particle from a ^{228}_{88}Ra nucleus means a gain of 1 in the atomic number with no essential change in mass. The new nuclide will have an atomic number of  ( Z + 1), or 89, which is actinium, Ac:

^{228}_{88}Ra → ^{228}_{89}Ac   +  ^0_{-1}e