Reaction: 2 Marks
Symbols: 1 Mark
Representation of P and Q: 2 Marks
The symbolic representation of the reaction is as follows:
AZXβ−particle−−−−−−→Mβ−particle−−−−−−→Nα−particle−−−−−−→PQY
From the above, the symbol of
M=AZ+1M and N=AZ+2N
Since, N nucleus loses one alpha - particle, therefore, the new nucleus has:
mass number = A - 4
Atomic number = Z + 2 - 2 = Z
Hence, P = A - 4 and Q = Z