There are two ways to define the “heaviest” elements – based on their density or atomic mass.
The heaviest element in terms of density can be defined as mass per unit volume, usually measured in grams per cubic centimeter or kilograms per cubic metre.
The densest naturally occurring element on earth is osmium.
Another way to look at gravity is atomic weight, the average mass of an element’s atoms.
This is a fundamental concept in chemistry because most chemical reactions proceed according to the simple numerical relationships between atoms.
Below we have listed the seven heaviest elements found on earth according to their atomic masses.
Note: We have not mentioned elements whose properties are unknown or not yet confirmed, such as moscovium, flerovium, nihonium and meitnerium.
Rutherfordium (Rf) was the first superheavy element to be discovered [1964].
It is highly radioactive and its most stable isotope, 267Rf, has a half-life of about 78 minutes.
Rutherfordium is an artificial element created in the laboratory by bombarding Californium-249 with a carbon-12 nucleus.
A total of 16 isotopes with atomic masses between 253 and 270 have been reported.
The element is expected to be a solid under normal conditions and is believed to have chemical properties similar to hafnium.
It was only produced in tiny quantities and used only for scientific research.
Dubnium (Db) is a radioactive element first synthesized in 1968 at the Joint Nuclear Research Institute, Russia.
It has seven recognized isotopes, the most stable of which is 268 dB with a half-life of 32 hours.
Dubnium can be made by bombarding either Californium-249 with nitrogen or Americium-243 with neon.
A limited study of dubnium chemistry has confirmed that the element behaves more like niobium than tantalum, breaking periodic trends.
Because the element is not found freely in nature, nor is it manufactured in large quantities in the laboratory, it has no uses other than scientific research.
The research team bombarded Californium-249 with Oxygen-18 nuclei to create Seaborgium-263.
It is a radioactive element whose most stable isotope (269Sg) has a half-life of about 14 minutes.
Few seaborgium atoms have ever been made, and their use is strictly for scientific research.
The little research that has been done on this synthetic chemical element shows that seaborgium is a dense heavy metal under normal conditions.
In 2014, Japanese researchers first made a chemical bond between a carbon atom and seaborgium, opening new doors for analyzing the impact of Einstein’s theory of relativity on the structure of the periodic table.
Bohrium (Bh) is a man-made radioactive element named after the famous physicist Niels Bohr.
Since it decays very quickly by emitting alpha particles (270Bh has a half-life of 61 seconds), the element is very difficult to study.
Bohrium does not occur in nature and only a few atoms have been produced so far.
Hassium (Hs) was discovered by German physicists in 1984 and is one of the heaviest and most dense elements in the periodic table.
All nine isotopes of the element have very short half-lives: the most stable (270 hs) has a half-life of 10 seconds.
So far only a few hassium atoms have been produced.
Although the exact melting point, boiling point, and density are unconfirmed, the element is believed to be a solid at room temperature.
This radioactive transition metal could react with other elements [of its group] if produced in large quantities.
Until now, it has no commercial use other than scientific research.
Tennessine (Ts) is the second heaviest known element, discovered by a Russian-American collaboration in 2010.
It is a radioactive, man-made element.
Tennessine was produced by a fusion reaction of calcium-48 with berkelium-249.
Tennessine’s use is limited to research purposes due to its tiny production.
Its most stable isotope (294Ts) has a half-life of about 80 milliseconds, decaying by alpha decay.
Read: 15 Densest Materials on Earth | volumetric mass density
First synthesized in 2002, oganesson (Og) is the heaviest element on the periodic table.
This highly radioactive element belongs to the group of noble gases.
Only six atoms of oganesson have been identified since 2005.
Since oganesson is very unstable (having a half-life of around 0.89 milliseconds) and does not occur naturally, there is almost no reason to consider its health risks.
Heaviest naturally occurring element: uranium
Uranium glass glowing under ultraviolet light | Photo credit: Wikimedia Commons
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Atomic Mass: 238.0289
Although uranium is a radioactive element, its rate of decay is much slower than other elements associated with radioactivity.
Its most natural form (uranium-238) has a half-life of about 4.5 billion years.
Read: 15 Fascinating Facts About Uranium | A weakly radioactive metal
Uranium is mainly used as a nuclear fuel to generate electricity in nuclear power plants.