CBSE Class 12-science Answered
Hi dear,
When a nucleon ( proton or neutron) is added to the nucleus, nuclear force attracts it to other nucleons.
Since smaller nucleii have a large surface area to volume ratio, the binding energy per nuceon due to nuclear force increases with the size of nucleus .
The electrostatic force on the other hand, is an inverse square force, so a proton added to a nucleus will feel an electrostatic repulsion from all the other protons in the nucleus. The electrostatic force increases without limit as nucleii get larger.
The net result of these opposing force generally increases, with incresing size, upto elements iron and nickel,and then decreses for heavier nuclei. The very heavy nuclei are not stable.
Hope this helps.
Regards
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