The difference between the sum of masses of all nucleons ( M ) mass of the nucleus ( m ) is called mass defect .
Mass Defect ( Δm ) = M – m = [ Zm p + ( A – Z ) m n – m n ]
Nuclear Binding Energy
The minimum energy required to separate the nucleons up to an infinite distance from the nucleus , is called nuclear binding energy .
Nuclear binding energy per nucleon = Nuclear binding energy / Total number of nucleons
Binding energy , E b = [ Zm p + ( A – Z ) m n – m N ] c 2
Packing Fraction ( P )
p = ( Exact nuclear mass ) – ( Mass number ) / Mass number
= M – A / M
The larger the value of packing friction . greater is the stability of the nucleus .
[ The nuclei containing even number of protons and even number of neutrons are most stable .
The nuclei containing odd number of protons and odd number of neutrons are most instable .]
Radioactivity
The phenomena of disintegration of heavy elements into comparatively lighter elements by the emission of radiations is called radioactivity . This phenomena was