Thorium (Th) – Periodic Table [Element Information & More]

thorium element periodic table

Thorium element (Th) is in period 7 of a periodic table. Thorium is in the f-block and it is classified as a lanthanide on the periodic table.

There is a lot more information related to thorium which is mentioned in the Information Table given below.

So let’s dive right into it!

Table of contents

Thorium Element (Information Table)

The important data related to thorium element is given in the table below.

Appearance of thoriumSilvery white appearance
Atomic number of thorium90
Symbol of thoriumTh
Atomic mass of thorium232.04 u
Protons, Neutrons & Electrons in thoriumProtons: 90, Neutrons: 142, Electrons: 90
State of thorium (at STP)Solid
Period number of thorium in periodic table7
Block of thorium in periodic tablef-block
Category of thoriumInner transition metals
Bohr model or Electrons per shell or Electrons arrangement in thorium2, 8, 18, 32, 18, 10, 2
Electron configuration of thorium[Rn] 6d2 7s2
Orbital diagram of thoriumorbital diagram of thorium
Electronegativity of thorium (on pauling scale)1.3
Atomic radius of thorium (van der Waals radius)237 picometers
Density of thorium11.725 g/cm3
1st ionization energy of thorium6.08 eV
Main isotope of thorium232Th
Melting point of thorium2023 K or 1750 °C or 3182 °F
Boiling point of thorium5061 K or 4788 °C or 8650 °F
Crystal structure of thoriumFace Centered Cubic (FCC)
Discovery of thoriumBy Jons Jakob Berzelius in 1829

Also see: Interactive Periodic Table (It has rotating bohr models as well as many other details of all the 118 elements in a single periodic table).

Thorium element in Periodic table

The Thorium element (Th) has the atomic number 90 and is located in period 7. Thorium is a metal and it is classified as an actinide group element.

Click on above elements in the periodic table to see their information.

Facts about thorium

Here are a few interesting facts about thorium element.

  1. Jons Jakob Berzelius was the chemist who discovered thorium in the year 1829.
  2. Thorium was given its name from the name “Thor”, which is the name of Norse god of thunder.
  3. Thorium is around 6 ppm by weight in the earth’s crust.
  4. The main ores of thorium are thorite, thorianite and monazite. Majority of thorium is obtained from these ores.
  5. Australia, Canada, US, Russia and India are the major regions from where thorium is mined.

Properties of thorium

Here is a list of some physical properties and chemical properties of thorium.

Physical properties of thorium

  • Thorium has a silvery white appearance.
  • The density of thorium is 11.725 g/cm3 and its atomic mass is 232.04 amu.
  • There are many isotopes of thorium, but the most stable isotope is 232Th and it has a half-life of 14 billion years.
  • Thorium has a FCC crystal structure.
  • The melting point and boiling point of thorium is 2023 K and 5061 K respectively.

Chemical properties of thorium

  • When thorium is kept open in the air, it starts tarnishing and forms a thin oxide layer on it.
  • Thorium reacts with water and this chemical reaction is slow.
  • Thorium gets dissolved in HCl.
  • Thorium also reacts with elements like hydrogen, sulfur, chlorine, fluorine, bromine, etc.
  • Thorium has many oxidation states, but the most common oxidation state is +4.

Uses of thorium

Here are some uses of the thorium element.

  • Thorium metal is added to magnesium metal, which gives strength to magnesium.
  • Thorium dioxide is used in manufacturing of glass to increase its refractive index.
  • Thorium dioxide is also added to ceramics which increases its resistance against higher temperatures.
  • Thorium and uranium are also responsible for the heat present in the earth’s crust.

External resources:

  1. Thorium – Element information, properties and uses | Periodic Table. (n.d.). Thorium – Element Information, Properties and Uses | Periodic Table.
  3. It’s Elemental – The Element Thorium. (n.d.). It’s Elemental – the Element Thorium.
  4. Thorium – World Nuclear Association. (n.d.). Thorium – World Nuclear Association.
  5. P. (n.d.). Thorium | Th (Element) – PubChem. Thorium | Th (Element) – PubChem.
  6. Thorium. (n.d.). Thorium.
  7. Thorium | CCDC. (n.d.). Thorium | CCDC.
  8. Periodic Table of Elements: Los Alamos National Laboratory. (n.d.). Periodic Table of Elements: Los Alamos National Laboratory.
  9. Atomic Weight of Thorium | Commission on Isotopic Abundances and Atomic Weights. (n.d.). Atomic Weight of Thorium | Commission on Isotopic Abundances and Atomic Weights.
  10. Atomic Data for Thorium (Th). (n.d.). Atomic Data for Thorium (Th).
  11. Haynes, W. M. (Ed.). (2014, June 4). CRC Handbook of Chemistry and Physics.
  12. Kaye, G W.C., & Laby, T H. Tables of physical and chemical constants. 15th Edition. United States.
  13. Sansonetti, J. E., & Martin, W. C. (2005, December). Handbook of Basic Atomic Spectroscopic Data. Journal of Physical and Chemical Reference Data, 34(4), 1559–2259.
  14. Bondi, A. (1964, March). van der Waals Volumes and Radii. The Journal of Physical Chemistry, 68(3), 441–451.
  15. Holden, et al. (2018, December 1). IUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the Education Community (IUPAC Technical Report). Pure and Applied Chemistry, 90(12), 1833–2092.
  16. Emsley, J. (2011). Nature’s Building Blocks: An A-Z Guide to the Elements. United Kingdom: OUP Oxford.
  17. Allred, A. (1961, June). Electronegativity values from thermochemical data. Journal of Inorganic and Nuclear Chemistry, 17(3–4), 215–221.
  18. James A. M. & Lord M. P. (1992). Macmillan’s chemical and physical data. Macmillan.
  19. Zhang, Y., Evans, J. R. G., & Yang, S. (2011, January 11). Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. Journal of Chemical & Engineering Data, 56(2), 328–337.
  20. Possolo, A., van der Veen, A. M. H., Meija, J., & Hibbert, D. B. (2018, January 4). Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report). Pure and Applied Chemistry, 90(2), 395–424.

Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online learning platform that provides students with easily understandable explanations.

Read more about our Editorial process.

Leave a Comment