Correct Answer - 1
The atoms of the elements having same atomic number but different mass numbers are called isotopes.
(1) `_(Z)^(A)X overset(-alpha)(rarr)_(Z-2)^(A-4)Y` (2) `_(Z)^(A)Xoverset(-beta)(rarr)_(Z+1)^(A)Y` (3) `_(Z)^(A)Xoverset(`-_(0)^(1)n)(rarr)_(Z)^(A-1)Y X` (4) `_(Z)^(A)Xoverset(-beta+)(rarr)_(Z-1)^(A)Y`
