A radioactive nucleus emits 4 particles and 7 particles in succession. The ratio of number of neutrons to that of protons is [ A = mass number, Z = atomic number ]

Step-by-step solution

Let us assume, a particle X having atomic number Z and mass number A . When an a-particle is emitted by a nucleus, then its atomic number decreases by 2 and mass number decreases by 4 . So, for given case, Z X ^ A 4 a-particle Z _ - a Y ^ A -16 When a -particle is emitted by a nucleus its atomic number increases by one and mass number remains unchanged. So, for given case, Z -8 Y ^ A -16 7 -p a r t i c l e Z -1 Z ^ A -16