CBSE Class 12-science Answered

If the proton and neutron are part of an atomic nucleus, these decay processes transmute one chemical element into another. For example:

13755Cs			→	13756Ba	+	e−	+	νe	(beta minus decay)
2211Na			→	2210Ne	+	e+	+	νe	(beta plus decay)
2211Na	+	e−	→	2210Ne	+	νe			(electron capture)

Beta decay does not change the number of nucleons, A, in the nucleus but changes only its charge, Z. Thus the set of all nuclides with the same A can be introduced; these isobaric nuclides may turn into each other via beta decay. Among them, several nuclides (at least one) are beta stable, because they present local minima of the mass excess: if such a nucleus has (A, Z) numbers, the neighbour nuclei (A, Z−1) and (A, Z+1) have higher mass excess and can beta decay into (A, Z), but not vice versa.