What is Thorium Definition Atomic Number Electron Configuration Properties and Uses
Here Are The Chemical Properties Of Thorium
Group - Actinides
Period – 7
Block – f
Atomic number – 90
State at 20°C – Solid
Electron configuration - [Rn] 6d27s2
Melting point - 1750°C, 3182°F,2023K
Boiling point - 4785°C, 8645°F , 5058K
Density (g cm−3) - 11.7
Relative atomic mass - 232.038
Key isotopes - 230Th, 232Th
CAS number - 7440-29-1
Thorium – What is it?
Thorium belongs to the actinide family. These are the elements that are placed on Row7 of the periodic table. The actinides have an atomic number between 90 and 103.
Thorium is an element that was discovered by a Swedish chemist named Jons Jakob Berzelius in the year 1828. He, however, did not know what thorium is and that it is a radioactive element. This was discovered in 1898 by Marie Curie, who was a Polish-French physicist as well as by Gerhard C. Schmidt, who was an English chemist.
Berzelius found a new element in the Falun district in Sweden, and he knew that it was a new element. The name thorium came in honour or the Scandinavian god Thor.
Here are The Physical Properties of Thorium
Thorium is a soft and silvery-white metal which looks somewhat like lead. It can be bent, cut, rolled, hammered, shaped or welded easily.
The physical properties of thorium are similar to that of lead. The melting point of thorium is 1,800°C (3,300°F), and its boiling point is 4,500°C (8,100°F). The density of thorium is 11.7 grams per cubic centimeter.
The pure form of thorium is air-stable, and it can retain its luster for many months. However, when thorium gets contaminated with oxide, then it starts to tarnish in air, and this changes its colour to grey and then to black. The melting point of thorium is one of the highest among all the oxides.
Thorium is attacked only slowly with water. However, it does not dissolve in most of the acids easily. This is except in hydrochloric acid. The powdered form of thorium is pyrophoric, and it should be handled with care. When thorium is heated in the air, then it burns with a bright white light.
Thorium – Its Applications
Before the radioactive property of thorium was known, there was a lot of retail use of thorium and its compounds. It was used in toothpaste and gas mantles.
Thorium is still used in magnesium as an alloying element. It is used to cast the tungsten wire and finds use in the electronic equipment to control the plutonium grain size that finds application in the electric lamps.
Thorium is also used in the metallurgical industries in the manufacture of refractory materials.
Thorium oxide also finds use in the laboratory cubicles with a high temperature.
Thorium, when added to the glass, creates a glass that has a high refractive index and a low dispersion.
It is being studied to use thorium as a source of nuclear fuel. Thorium will find use in the nuclear reactor to burn it without generating plutonium. Thorium is also used to date the hominid fossils.
Thorium – Its Health Effects
Thorium is present everywhere on earth, and thus people are always exposed to it in small amounts. We get exposed to thorium energy through water, air and the food that we eat.
Large amounts of uncontrolled thorium could be found near the waste sites where the thorium has not been disposed of as per the proper procedure. This is hazardous. Those who live close to these sites are exposed to high amounts of thorium because they breathe more thorium and also have food that is grown in the site, which is high in thorium.
Those who work in the thorium, milling and mining industries are also exposed to thorium which is more than the natural exposure.
Breathing excess thorium could cause lung diseases and pancreatic cancer. Thorium can also change one's genetic materials.
Those who have been injected with thorium, for some special x-ray could also develop liver disease.
Thorium is radioactive in nature, and it thus gets stored in the bones. This is why exposure to thorium can cause bone cancer. These harmful health effects are seen many years of being exposed to thorium.
If one breathes massive amounts of thorium, then this could be lethal for one's health. People could die because of metal poisoning when there is massive exposure to thorium.
FAQs on Thorium Element Atomic Structure Properties and Uses
1. What is thorium in chemistry?
Thorium is a naturally occurring radioactive chemical element with atomic number 90 and symbol Th in the actinide series. It is a silvery-white metal that slowly tarnishes in air and is primarily found in minerals like monazite sand. In the periodic table, thorium belongs to the f-block (actinides) and commonly exhibits an oxidation state of +4. It is important in nuclear chemistry because 232Th can be used as a fertile material in nuclear reactors.
2. What is the electron configuration of thorium?
The electron configuration of thorium (Z = 90) is [Rn] 6d2 7s2. This means:
- Thorium has the radon core [Rn] (86 electrons).
- It has 4 valence electrons distributed in the 6d and 7s orbitals.
- These valence electrons allow thorium to commonly form Th4+ ions.
Its electron configuration explains its typical +4 oxidation state in thorium compounds.
3. What is the most common oxidation state of thorium?
The most common oxidation state of thorium is +4. In most thorium compounds, thorium loses four electrons to form the Th4+ ion. Examples include:
- ThO2 (thorium dioxide)
- ThCl4 (thorium tetrachloride)
- Th(NO3)4 (thorium nitrate)
Lower oxidation states such as +3 are rare and much less stable compared to +4.
4. Is thorium radioactive?
Yes, thorium is naturally radioactive and primarily exists as the isotope 232Th. Key facts include:
- 232Th has a very long half-life of about 1.4 × 1010 years.
- It undergoes alpha decay to eventually form stable 208Pb.
- It belongs to the thorium decay series in nuclear chemistry.
Although radioactive, its long half-life means it decays very slowly compared to many other radioactive isotopes.
5. What is thorium dioxide (ThO2)?
Thorium dioxide (ThO2) is a stable, white, crystalline oxide formed when thorium reacts with oxygen. It can be formed by the reaction:
Th(s) + O2(g) → ThO2(s)
- Thorium is in the +4 oxidation state.
- It has a very high melting point (about 3300 °C).
- It is used in nuclear fuel research and high-temperature ceramics.
ThO2 is one of the most important thorium compounds in inorganic and nuclear chemistry.
6. How does thorium react with acids?
Thorium reacts slowly with dilute acids to form thorium(IV) salts and hydrogen gas. For example, with hydrochloric acid:
Th(s) + 4HCl(aq) → ThCl4(aq) + 2H2(g)
- Thorium is oxidized to Th4+.
- Hydrogen ions are reduced to H2 gas.
- Concentrated nitric acid may passivate the metal surface.
This reaction is characteristic of reactive metals forming +4 oxidation state compounds.
7. What is the role of thorium in nuclear reactors?
Thorium-232 is a fertile material that can be converted into fissile uranium-233 in a nuclear reactor. The key nuclear process is:
- 232Th + n → 233Th
- 233Th undergoes beta decay to 233Pa
- 233Pa further beta decays to 233U (fissile)
This makes thorium important in the thorium fuel cycle, studied as an alternative to uranium-based nuclear fuel.
8. What are the physical properties of thorium?
Thorium is a dense, silvery, radioactive metal with a high melting point and good mechanical strength. Key physical properties include:
- Atomic number: 90
- Atomic mass: 232.04 g·mol-1
- Melting point: about 1750 °C
- Density: about 11.7 g·cm-3
It is softer than uranium and can be rolled into sheets when pure.
9. What is the difference between thorium and uranium?
The main difference between thorium and uranium is that thorium is fertile while natural uranium contains fissile isotopes. Key differences:
- Thorium (Z = 90) mainly exists as 232Th (fertile).
- Uranium (Z = 92) contains 235U, a naturally fissile isotope.
- Thorium must be converted into 233U to sustain a chain reaction.
Both are actinides used in nuclear chemistry, but their fuel cycles differ significantly.
10. Where is thorium found in nature?
Thorium is found in nature mainly in the mineral monazite, which contains thorium phosphate. Important points:
- It occurs in trace amounts in the Earth’s crust (about 10 ppm).
- Major deposits are found in India, Australia, Brazil, and the United States.
- It is obtained by chemical processing of monazite sands.
Thorium is more abundant in the Earth’s crust than uranium, making it significant in discussions of alternative nuclear fuels.
