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Thorium

physical science Maturity 11-13

Thorium is a special metal.

Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
It is bright and silver. It is found in the ground. It can help make power. It is very old. Do you like silver?

37 words

Thorium is a special metal.

Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
It is bright and silver. It can be bent or shaped. A scientist found it in a rock. He named it after a god of thunder.

This metal is very old. It stays in the ground for a long time. It can even be used to make power.

Indian Point Nuclear Power Plant.jpg
Indian Point Nuclear Power Plant.jpg
People use it in things like light bulbs and engines. It is a very useful metal.

91 words

Thorium is a bright, silver metal.

Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
It is a soft metal that can be bent or shaped. A chemist named Jöns Jacob Berzelius found it in 1828. He found it in a mineral from Norway. He named the metal after Thor, the Norse god of thunder.
J J Berzelius.jpg
J J Berzelius.jpg

Thorium is radioactive. This means it gives off energy in a special way. All types of thorium are unstable. This means they change over time. The most stable kind is called 232Th. It has a half-life of 14 billion years. A half-life is the time it takes for half of a sample to change. This is about as old as the universe!

Decay Chain Thorium.svg
Decay Chain Thorium.svg

Thorium is very common. It is three times more common than uranium in the Earth's crust. People find it in monazite sands. Scientists use it for many things. It helps make magnesium stronger. It is used in aircraft engines and light bulbs. Some people think it can be used as fuel for nuclear reactors.

Indian Point Nuclear Power Plant.jpg
Indian Point Nuclear Power Plant.jpg

190 words

Thorium is a bright, silver metal that is quite interesting to scientists. It is an actinide, which is a group of heavy elements.

Thorium half sandwich.svg
Thorium half sandwich.svg
This metal is moderately soft and can be bent or shaped. It is also malleable, meaning it can be pressed into thin sheets.
CaF2 polyhedra.png
CaF2 polyhedra.png
When thorium is exposed to the air, it changes color. It turns an olive grey color because it forms thorium dioxide. This metal has a very high melting point of 1750 °C. It is much higher than other elements like actinium or protactinium.
Kristallstruktur Uran(IV)-fluorid.png
Kristallstruktur Uran(IV)-fluorid.png

Thorium is radioactive, which means its atoms are unstable. All known versions of thorium are unstable and will change over time.

Decay Chain Thorium.svg
Decay Chain Thorium.svg
The most stable version is called 232Th. It has a half-life of 14 billion years. This is about as old as the entire universe! This version changes through a process called alpha decay. This starts a long chain of changes called the thorium series. This series eventually ends when it becomes a stable metal called lead.

A Swedish chemist named Jöns Jacob Berzelius discovered thorium in 1828.

J J Berzelius.jpg
J J Berzelius.jpg
He found it while studying a new mineral. This mineral was found by Morten Thrane Esmark in Norway. The mineral came from an island called Lovoya near the Langesund fjord. Berzelius gave the metal its name after Thor. Thor was the Norse god of thunder and war. This name has helped people remember this powerful element for a long time.

Thorium is very common in our world. It is estimated to be over three times as abundant as uranium in the Earth's crust.

Seaborg in lab - restoration.jpg
Seaborg in lab - restoration.jpg
Most thorium is refined from monazite sands. It is often found as a by-product when people extract rare-earth elements. Scientists use different versions of thorium for many jobs. Some thorium is used in cancer treatments to help people. Other types are used to help scientists understand the ancient ocean.
Yellowing of thorium lenses.jpg
Yellowing of thorium lenses.jpg
Researchers use the ratio of isotopes to date old ocean sediments.

We use thorium in many things we see every day. It was once used as a light source in gas mantles.

Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
It was also used in high-end camera lenses and scientific tools. Today, it is used to make magnesium stronger for different machines. It can also be used in aircraft engines and light bulbs.
Indian Point Nuclear Power Plant.jpg
Indian Point Nuclear Power Plant.jpg
Some people suggest using thorium as a new kind of fuel for nuclear reactors. This could change how we make energy in the future. It is a very useful metal with many different roles.

458 words

Thorium is a chemical element with the symbol Th and the atomic number 90. It is classified as an actinide, which is a group of heavy, radioactive metallic elements.

Thorium half sandwich.svg
Thorium half sandwich.svg
Thorium is a bright, silvery metal that is moderately soft and malleable. This means it can be bent, shaped, or pressed into thin sheets. When exposed to air, it reacts to form thorium dioxide, which gives the metal an olive-grey tarnish.
CaF2 polyhedra.png
CaF2 polyhedra.png
Thorium is an electropositive element, meaning it tends to lose electrons easily. Its chemistry is largely defined by the +4 oxidation state. This metal is also quite reactive; if it is divided into fine particles, it can actually ignite in the air.

Decay Chain Thorium.svg
Decay Chain Thorium.svg
The physical structure of thorium changes depending on its environment. At room temperature, it has a face-centered cubic crystal structure. However, if you heat it above 1360 °C, it shifts to a body-centered cubic structure. Under extreme pressure of around 100 GPa, it adopts a body-centered tetragonal structure. Thorium has a very high melting point of 1750 °C. This is significantly higher than its neighbors, actinium and protactinium. This high melting point occurs because the number of delocalized electrons increases as you move toward thorium. These electrons create a stronger attraction between the metal ions, which holds the structure together more tightly.

J J Berzelius.jpg
J J Berzelius.jpg
Thorium was discovered in 1828 by the Swedish chemist Jöns Jacob Berzelius. He identified the element while analyzing a new mineral found in Norway. This mineral was discovered by Morten Thrane Esmark on the island of Løvøya. Berzelius chose to name the element after Thor, the Norse god of thunder and war. In the early 20th century, scientists began to widely acknowledge its radioactivity. During the second half of the 20th century, many applications of thorium changed. People began to replace thorium in various products due to concerns regarding its radioactive properties.

Decay Chain Thorium.svg
Decay Chain Thorium.svg
All known isotopes of thorium are unstable, meaning they undergo radioactive decay. The most stable isotope is 232Th, which has a half-life of 14.0 billion years. This duration is roughly the age of the universe. This isotope decays through a process called alpha decay, where the nucleus releases an alpha particle. This begins the thorium series, a chain of consecutive alpha and beta decays. This long process eventually results in the stable element lead-208. Thorium and uranium are the only elements that occur naturally in large quantities as primordial elements. This means they have existed since the Earth was formed without being completely decayed away.

Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
Thorium is surprisingly common in the Earth's crust. It is estimated to be over three times as abundant as uranium. Most thorium is refined from monazite sands. It is usually collected as a by-product during the extraction of rare-earth elements. Because of its abundance and potential, researchers have suggested using thorium as a replacement for uranium in nuclear reactors. Several thorium-based reactors have already been built to explore this possibility.

Yellowing of thorium lenses.jpg
Yellowing of thorium lenses.jpg
Thorium has been used in many specialized industrial and scientific roles. It is used as an alloying element in TIG welding electrodes. It is also used to strengthen magnesium and to coat tungsten wire in electrical equipment. In the past, thorium was a common material in high-end optics and scientific lenses.
Indian Point Nuclear Power Plant.jpg
Indian Point Nuclear Power Plant.jpg
However, thorium can cause lenses to yellow over time. It was also used in gas mantles to provide light and in certain broadcast vacuum tubes. While some of these uses are now marginal, thorium remains important in heat-resistant ceramics and aircraft engines.

Decay Chain Thorium.svg
Decay Chain Thorium.svg
Scientists also use thorium to study the history of our planet. Two specific methods, uranium–thorium dating and ionium–thorium dating, help determine the age of materials. Uranium–thorium dating is used on calcium carbonate, such as coral or cave formations called speleothems. This works because uranium is more soluble in water than thorium. Ionium–thorium dating measures the ratio of 232Th to 230Th in ocean sediments. These methods allow oceanographers to understand the ancient ocean by looking at how these isotopes settle over time.

702 words
🖼️ Images & Media (13)
File:Decay Chain Thorium.svg
Decay Chain Thorium.svg
File:CaF2 polyhedra.png
CaF2 polyhedra.png
File:Kristallstruktur Uran(IV)-fluorid.png
Kristallstruktur Uran(IV)-fluorid.png
File:Uranocene-3D-balls.png
Uranocene-3D-balls.png
File:Thorium half sandwich.svg
Thorium half sandwich.svg
File:Evolution of Earth's radiogenic heat-no total.svg
Evolution of Earth's radiogenic heat-no total.svg
File:Mårten Eskil Winge - Tor's Fight with the Giants - Google Art Project.jpg
Mårten Eskil Winge - Tor's Fight with the...
File:J J Berzelius.jpg
J J Berzelius.jpg
File:Old thorium dioxide gas mantle - oblong shape.JPG
Old thorium dioxide gas mantle - oblong shape.JPG
File:Seaborg in lab - restoration.jpg
Seaborg in lab - restoration.jpg
File:Indian_Point_Nuclear_Power_Plant.jpg
Indian_Point_Nuclear_Power_Plant.jpg
File:Yellowing of thorium lenses.jpg
Yellowing of thorium lenses.jpg

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