Question
If uranium (mass number 238 and atomic number 92) emits an $$\alpha $$ -particle, the product has mass no. and atomic no.
A.
236 and 92
B.
234 and 90
C.
238 and 90
D.
236 and 90
Answer :
234 and 90
Solution :
$$\eqalign{
& {}_{92}{U^{238}}{ \to _{90}}{U^{234}} + _2^4He \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\left( {\alpha - {\text{particle}}} \right) \cr} $$