CGPET 2013 Solved Paper

The stability of a nucleus depends upon the neutron to proton (‌

n

p

) ratio in the nucleus.
Thus,
(i) The lower elements (upto Z=20 ), the stable nuclei have about equal number of protons and neutrons i.e., ‌

n

p

=1 e.g., ‌2040‌Ca,‌1327‌Al
(ii) For higher elements to be stable, there must be more neutrons than protons i.e., ‌

p

p

>1. e.g., ‌2555‌Mn,‌50119‌Sn