
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)
- Thorium element in Periodic table
- Facts about Thorium
- Properties of Thorium
- Uses of Thorium
Thorium Element (Information Table)
The important data related to thorium element is given in the table below.
Appearance of thorium | Silvery white appearance |
Atomic number of thorium | 90 |
Symbol of thorium | Th |
Atomic mass of thorium | 232.04 u |
Protons, Neutrons & Electrons in thorium | Protons: 90, Neutrons: 142, Electrons: 90 |
State of thorium (at STP) | Solid |
Period number of thorium in periodic table | 7 |
Block of thorium in periodic table | f-block |
Category of thorium | Inner transition metals |
Bohr model or Electrons per shell or Electrons arrangement in thorium | 2, 8, 18, 32, 18, 10, 2 |
Electron configuration of thorium | [Rn] 6d2 7s2 |
Orbital diagram of thorium | ![]() |
Electronegativity of thorium (on pauling scale) | 1.3 |
Atomic radius of thorium (van der Waals radius) | 237 picometers |
Density of thorium | 11.725 g/cm3 |
1st ionization energy of thorium | 6.08 eV |
Main isotope of thorium | 232Th |
Melting point of thorium | 2023 K or 1750 °C or 3182 °F |
Boiling point of thorium | 5061 K or 4788 °C or 8650 °F |
Crystal structure of thorium | Face Centered Cubic (FCC) |
Discovery of thorium | By 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.
H | He | ||||||||||||||||
Li | Be | B | C | N | O | F | Ne | ||||||||||
Na | Mg | Al | Si | P | S | Cl | Ar | ||||||||||
K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
Cs | Ba | La* | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
Fr | Ra | Ac** | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
*Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | ||||
**Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr |
Facts about thorium
Here are a few interesting facts about thorium element.
- Jons Jakob Berzelius was the chemist who discovered thorium in the year 1829.
- Thorium was given its name from the name “Thor”, which is the name of Norse god of thunder.
- Thorium is around 6 ppm by weight in the earth’s crust.
- The main ores of thorium are thorite, thorianite and monazite. Majority of thorium is obtained from these ores.
- 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.
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