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Radioactive Isotopes

Radioactive Isotopes of Lead Uranium & Thorium

Radioactive isotopes or radioisotopes of an element have the same atomic number (electron) but different in mass numbers due to varying numbers of the neutron particles inside the nucleus of an atom. The stable radioactive isotopes in learning chemistry possess identical properties and chemical reactions because of their identical electronic configuration. But the radioactive properties of isotopes that depend on the nucleus are different. Isotopes of lead, uranium, thorium, iodine, sodium, and cobalt uses by researchers in radioactive medicine in radiotherapy, biological chemistry, agricultural chemistry, trace chemical analysis, and radioactive nuclear power generation process.

Applications of the uses of radioactive isotopes or radioisotopes mainly in radiotherapy for cancer treatment or use electromagnetic spectrum radiation in medicine, analytical chemistry, and age determination of hydrocarbon or carbon compounds or mineral. Continuous emission of alpha, beta, and gamma rays of uranium and thorium from the most stable radioactive isotopes of lead. This process forming the list of radioactive decay series or chain for physics and chemistry learning.

Radioactive Emission of Alpha and Beta Rays

  1. Emission of alpha rays within the radioactive atoms loses two units of atomic number and four units of mass number. If the radioactive element having mass number = M and atomic number = Z. After the emission of the alpha particle, the atomic and mass number of newborn elements = (Z – 2) and (M – 4) respectively.
  2. But for the emission of beta rays from the radioactive nucleus increases the atomic number by one unit and mass numbers remain unchanged. Therefore, when an element ejected a beta ray the atomic number of newborn elements = (Z + 1).

Group Displacement Law and Radioactive Isotopes

In 1913 Soddy uses the law of radioactivity to describe the position of the radioactive isotopes in the periodic table known as group displacement law state as,

  1. When an alpha particle emitted in a radioactive decay step, the product displaced two places to the left in the periodic table.
  2. But the radiation of beta particles results in a displacement of the product to one place to the right.

The year when Soddy proposes group displacement law the knowledge of the atomic structure or electronic orbital configuration was still incomplete. He proposes this law by extensive chemical studies on the disintegration products of different radioisotopes. Soddy coined the term isotopes for such elements occupying the same position in the periodic table.

Decay Series of Radioisotopes

Uranium is the first discovered radioactive f-block elements with atomic number 92. Since uranium-238 successive decay to form the most stable isotopes of lead-208 is an example of radioactive decay series. Hence the mother element along with all the daughter elements converted to the stable isotope of lead to form a series of disintegration are called radioactive decay series.

Radioactive Decay of Uranium-238 to Lead-206

Uranium-238 decay to form the most stable isotope of lead-206. Therefore, the entire route involves eight alpha and six beta emission. The mass number of all the decay products given by 4n +2 (n = 59 for uranium-238). Therefore, these series are known as 4n +2 series ( n = an integer).

Radioactive isotopes of lead in uranium-238 disintegration series and uses of the isotope in chemistry

Uranium-235 and Thorium-232 Decay Series

Uranium-235 isotopes or (4n+3) series starts with uranium-235 and ends with lead – 207. Therefore, seven alpha and four beta radiate in the entire route of emission.

Radioactive isotopes in uranium-235, thorium-232 series and uses of radioisotopes in radiotherapy medicine

Thorium-232 undergoes successive decay to form the most stable radioactive isotopes of lead with mass number 208. Therefore, the entire decay chain of thorium-232 involves six alpha and four beta emission. This is the 4n radioactive decay series.

Analytical and Medicinal Uses of Radioactive Isotopes

Radioactive isotopes of carbon, oxygen, nitrogen, sodium, cobalt, iodine, sulfur, etc are very much used in different disciples (research, medicine, agriculture, trace analysis, and analytical problems). The uses of isotopes may be classified in the following heads like chemical analysis, medicine uses, for the determination of the age and agricultural analysis of fertilizer like sulphuric acid, nitric acid, phosphate fertilizer.

Uses of Isotopes in Chemical Analysis

  1. Isotopes have played a key role in the evaluation of the chemical kinetics reaction mechanism in organic chemistry test. Hence the mechanism of esterification easily evaluated by using oxygen isotope. Therefore, the process of esterification has two possible mechanisms. First carboxylic acid OH may react with the hydrogen atom of the alcohol to eliminate water. The second alcohol OH react carboxylic hydrogen of acid.
  2. Hydrolysis of ester carried out with water labeled by O-18 indicates that after hydrolysis O-18 formed acid solution in the reaction.
  3. A study with sulfur-35 has been using to establish the non-equivalency of the two sulfur atoms in thiosulfate ion.
  4. All the iodine in HgI4 ion are equivalent proved by studies with radioisotopes of iodine.

Uses of Radioactive Isotopes in Medicine

Radiation therapy of radioisotopes mainly uses as a weapon to kill the diseased tissue in the human body. It involves either external or internal sources of spectrum radiation.  Radioactive molecule and nuclear radiation produce during nuclear reactions affect our environmental pollution.

  1. Cobalt-60 is a useful gamma emitter with definite wavelengths of the radiation process. Therefore, cobalt-60 uses in radiation therapy. Cobalt-60 isotope inhibits the Millicent tissue or treatment of cancer in medicine.
  2. Iodine-131 uses in external radiation therapy for the treatment and diagnosis of thyroid glands in the human body.
  3. sodium-24 isotopes use in the abnormality of the blood circulation in the human body. Therefore, the doctor injected to the vein of the patient with sodium salt containing sodium-24 isotope.
  4. Phosphorus-32 isotope uses in leukemia therapy. Leukemia is the overproduction of white blood cells in the human body.

Therefore, the radioactive isotopes or radioisotopes in atomic chemistry uses mainly in trace chemical analysis (a trace amount of isotope mixed with a stable non-radioisotopes), radiotherapy in medicine, and agricultural fertilizer analysis. But stable radioactive isotopes of uranium, thorium, and lead of our environment uses mainly in the electric energy generation process for mankind.