NUCLEAR REACTIONS AND THEIR REPRESENTATION
Nuclear reactions involve the process of conversion of one nucleus into another artificially with the help of bombarding projectile. The process, in general can be represented as follows.
Target Bombarding New Ejected
+ à +
nuclide projectile nuclide particle
The nuclear reactions, in general, follow the following principles of conservation:
(i) Mass and energy. The total mass and energy before and after the nuclear change remains the same.
(ii) Mass number and atomic number. The sum total of mass numbers and that of atomic numbers before and after the nuclear change remains unaltered.
Representation of Nuclear Reactions
For the sake of brevity, the nature of nuclear reaction is represented by writing the bombarding projectile and ejected particle within brackets. For example, the nuclear reaction represented by equation (i) can be termed as (a, p) reaction because here, a-particle is a bombarding projectile and proton is the ejected particle. The same can be briefly represented as
It may be noted that out of various bombarding particles the neutrons are particularly useful because they do not carry any charge. On the other hand, the protons, deutrons and a -particles are positively charged particles and are repelled by the target nuclei. Some examples of nuclear reactions involving the use of different bombarding particles are as follows:
DIFFERENCE BETWEEN NUCLEAR AND CHEMICAL REACTIONS
Some important differences between the chemical reactions and nuclear reactions are given below in tabular form
1. No breaking or making of bonds is involved.
2. Generally proceed with tremendous release of energy.
3. Temperature and pressure do not affect their rates.
4. Such reactions are generally irreversible.
5. They involve the conversion of one nuclide into the other.
6. Large amount of energy is released for example loss of lu mass produces 931.48 MeV of energy.
1. They generally involve breaking of old bonds and formation of new chemical bonds.
2. They may involve evolution of absorption of
3. Their rates of reaction are affected by temperature and pressure conditions.
4.They can be reversible as well as irreversible.
5.They simply involve the rearrangement of atoms and do not involve any change in the nucleus.
6. In chemical reactions the amount of energy
released is much less because
qP = ΔH= HP -HR
It must be noted here that matter is not conserved in nuclear reactions. It is because energy is produced at the expense of loss in mass during the nuclear disintegration.