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Saturday, 25 April 2020

Interesting Facts about Nuclear Chemistry

Interesting Facts about Nuclear Chemistry


The branch of science which deals with the phenomenon of nuclei of atoms is known as nuclear chemistry.

The main cause of radioactive disintegration is the instability of the nucleus.

The phenomenon of spontaneous emission of active radiations from certain substances is called radioactivity and the substance emitting such radiations are called radioactive substances.

Radioactivity is classified into two types: natural radioactivity and artificial radioactivity.

If a substance emits radiations by itself, it is said to possess natural radioactivity.

If a substance does not possess radioactivity, but starts emitting radiation on exposure to rays from a natural radioactive substance, it is said to possess induced or artificial radioactivity.

Under the influence of electric and magnetic field, the radioactive rays split into three kinds. They are alpha (α), beta (β) and gamma (γ) rays.

Properties of Alpha rays:

1) Consists of positively charged particles.
2) It is represented by 2He4 (Helium nucleus)
3) Velocity of alpha particles is approximately 1/15th of that of light.
4) They can penetrate through thin metal foils.
5) They cause ionisation of gases
6) They can produce glow on a fluorescent screen.
7) They affect photographic plates.

Properties of Beta rays:

1) Consists of negatively charged particles.
2) Beta particles are nothing but electrons.
3) Velocity of beta particles ranges between 33 and 99% of that of light.
4) They have more penetrating power than alpha particles.
5) They cannot ionise gases as strongly as α-particles can.
6) They can produce glow on a fluorescent screen.
7) They affect photographic plates/films.

Properties of Gamma rays:

1) γ-rays are not deflected by magnetic or electric field.
2) They are not constituted of charged particles. γ-rays are a form of powerful electromagnetic radiation of very short wavelength.
3) Velocity of gamma rays equals that of light.
4) They have much higher penetrating power than β rays.
5) They can cause ionisation of gases.
6) They produce glow on fluorescent screen.
7) They affect photographic plates.

Group displacement law:

"The emission of an α-particle by a component results in the creation of a new component which lies two positions to the left of the parent component and the emission of β particle results in the creation of a new component which lies one position to the right of parent component in the periodic table".

Decay constant (λ) may be defined as the fraction of the total number of radioactive atoms disintegrating in unit time.

Half life period (t½): The half life period of a radioactive element is defined as the time required for the decay of one half of its original amount
t½ =  0.6932/λ

Artificial transmutation: The conversion of a stable nucleus into another nucleus by the bombardment of particles like protons, neutrons etc is known as artificial transmutation.

Artificial transmutation was discovered by Rutherford.

Nuclear fission is defined as the process of splitting of a heavy nucleus into two or more lighter nuclei by bombardment with a suitable sub-atomic particle.

Nuclear fission was discovered by Otto Hahn and Strassmann.             

Natural radioactivity was discovered by Henri Becquerel.

Artificial radioactivity was discovered by Irene Curie & F. Juliot.

The principle of atomic bomb is the uncontrolled nuclear fission reaction.

Nuclear fusion may be defined as a process in which two or more lighter nuclei combine to form a heavier nucleus.

Nuclear fusion occur only at very high temperatures. So these are called thermonuclear reactions.

The energy of sun is supposed to arise from nuclear fusion reaction.

The nuclear fusion reaction is the basis of the hydrogen bomb.

Simplest radioactive atom is Tritium (1H3).

Tritium is a beta emitter.

The daughter element of tritium is helium-3 (2He3).

Age of fossil can be found by radio carbon dating using carbon - 14.

Wine dating can be done by using tritium.

Rock-dating (Age of planet) can be calculated by Uranium dating by using U-238 and Ph - 206.

Radioactive Iodine (Iodine -131) is used for the treatment of hyper thyroidism.

Cobalt - 60 isotope is used for cancer treatment.

Deficit in blood circulation is identified by using phosphorus – 32.

Gold - 198 is used for the treatment of Leukemia.

Angiogram test is done by using sodium – 24.

Bone cancer can be diagnosed by using phosphorus - 32.

During beta emission isobars are produced.

Controlled fission reaction is done in nuclear reactor.

Five research reactor of India are Purnima, Zerlina. Dhruva, Cirus and Apsara at BARC.

 Important Power Stations in India are

1. Tarapur Atomic Power Station - Maharashtra
2. Rajasthan Atomic Power Station - Kota
3. Narora Atomic Power Station - Uttar Pradesh
4. Indira Gandhi Centre for Atomic Research -Kalpakkam (Chennai)

World's first fast breeder reactor named KA-MINI - Kalpakam (Chennai). The Kalpakkam reactor, has successfully used the mixed uranium - plutonium carbide fuel.

Unit of radioactivity is Becquerel (Bq).

1 Bq = I disintegration per second
1 Curie = 3.7 x 1010 Bq
1 Curie = 3.7 x 1010 dis/sec
1 Rutherford = 106 dis/sec

Radioactive disintegration of uranium ultimately results in the formation of lead.

Strongest radioactive element is radium.

Gaseous radioactive element is radon.

 Is green house effect responsible for global warming?

Yes, the green house effect is responsible for global warming.
Green house effect is the phenomenon in which earth's atmosphere traps the heat (IR radiation) from the sun and prevents it from re-radiating into the outer space. The gases like methane, carbon-dioxide, carbon monoxide, chlorofluoro carbon etc causes green house effect. The enhanced green house effect, lead to the over warming of the earth. This extra warming is called global warming.

What is Radio carbon dating?

Radio carbon dating is the technique of determining the age of old carboneous materials using the radio activity of carbon-14 isotopes.

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