Isobars
The atoms of different elements having same mass numbers but different atomic numbers , are called isobars .
e . g ., 1 H 3 , 2 He 3 and 10 Na 22 , 10 Ne 22 are isobars .
Isotones
The atoms of different elements having different atomic numbers and different mass numbers but having same number of neutrons , are called isotones .
e . g ., 1 H 3 , 2 He 4 and 6 C 14 , 8 O 16 are isobars .
Isomers
Atoms having the same mass number and the same atomic number but different radioactive properties are called isomers ,
Nuclear Force
The force acting inside the nucleus or acting between nucleons is called nuclear force . Nuclear forces are the strongest forces in nature .
� It is a very short range attractive force .
� It is non-central . non-conservative force .
� It is neither gravitational nor electrostatic force .
� It is independent of charge .
�
It is 100 times that of electrostatic force and 10 38 times that of gravitational force .
According to the Yukawa , the nuclear force acts between the nucleon due to continuous exchange of meson particles .
Mass Defect