Question

Complete the following nuclear reactions for α and β deca :

(i) `"_92^238U ->?  + _2^4He + Q`

(ii) `"_11^22Na ->?  + _10^22Ne + v`

Answer 1

(i) By balancing the atomic number and mass number we can easily find that the product will be an element with atomic number 90 and mass number 234, i.e. Thorium.  
`"_92^238U ->  + _90^234Th + _2^4He + Q`

(ii) As we can see there is no change in mass number during the reaction but the value of Z reduces by factor 1, hence we can conclude there is a positron beta decay happening in the reaction, so the missing product will be a positive beta particle.
The balanced reaction is as follows:
`"_11^22Na -> _10^22Ne + _1^0beta + v`