Question

A radioactive nucleus (initial mass number A and atomic number z) emits three   particles and two positrons. The ratio of number of neutrons to that of protons in the final nucleus will be

Answer 1

Answer:

Explanation:

alpha particle decrease atmic number by 2 and mass  number by 4

for 3 alpha decay

A -12 and Z -6

In case of positron that is beta+ emission,  Z value decrease by 1

for 2 such emission,  Z- 8 (6 from above )

therefor

Number of neuron = A -12 -Z +8 =A  -Z -8

number of proton =  Z- 8