There are two possible 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, which is usually measured in grams per cubic centimeter or kilograms per cubic meter.
The densest naturally occurring element on Earth is Osmium.
Another way of looking at heaviness is in terms of atomic weight, the average mass of the atoms of an element.
This is a fundamental concept in chemistry, because most chemical reactions occur according to simple numerical relationships between atoms.
Below, we have listed the seven heaviest elements found on Earth according to their atomic mass.
Note: We have not mentioned elements whose properties are unknown or unconfirmed, such as moscovium, flerovium, nihonium and meitnerium.
Rutherfordium (Rf) was the first super-heavy element to be discovered [in 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 California-249 with a Carbon-12 nucleus.
A total of 16 isotopes have been reported with atomic masses between 253 and 270.
The element is expected to be solid under normal conditions and assumed to have chemical properties similar to hafnium.
It was created only 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, of which the most stable is 268Db with a half-life of 32 hours.
Dubnium can be produced by bombarding either californium-249 with nitrogen or americium-243 with neon.
A limited examination of Dubnium’s chemistry confirmed that the element behaves more like niobium than tantalum, breaking periodic trends.
Since the element is neither found free in nature nor created in large quantities in the laboratory, it has no applications other than scientific research.
The research team bombarded californium-249 with oxygen-18 nuclei to produce seaborgium-263.
It is a radioactive element whose most stable isotope (269Sg) has a half-life of about 14 minutes.
Only a few atoms of seaborgium have ever been produced, and their use is only for scientific research.
The little research that has been done on this synthetic chemical element indicates that seaborgium is a dense, heavy metal under normal conditions.
In 2014, Japanese researchers established a chemical bond between a carbon atom and seaborgium for the first time, opening new doors to analyze the effects of Einstein’s relativity on the structure of the periodic table.
Bohrium (Bh) is an artificially produced radioactive element named after a famous physicist Niels Bohr.
Since it decays very quickly through the emission of alpha particles (270Bh has a half-life of 61 seconds), it is very difficult to study the element.
Bohrium is not found in nature, and only a few atoms have been produced to date.
Discovered by German physicists in 1984, Hassium (Hs) is one of the heaviest and densest elements in the periodic table.
All nine isotopes of the element have very short half-lives: the most stable (270Hs) has a half-life of 10 seconds.
So far, only a few hassium atoms have been produced.
Although the melting point, boiling point and density are not confirmed, the element is believed to be solid at room temperature.
This radioactive transition metal could react with other elements [of its group] if produced in large quantities.
So far, 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 element, produced artificially.
Tennessine was produced by a fusion reaction of calcium-48 with berkelium-249.
The use of tennessine is limited to research purposes due to its tiny production.
Its most stable isotope (294Ts) has a half-life of about 80 milliseconds, which decays through alpha decay.
Read: 15 Densest Materials on Earth | Volumetric mass density
First synthesized in 2002, Oganesson (Og) is the heaviest element in the periodic table.
This highly radioactive element is a member of the noble gas group.
As of 2005, only six Oganesson atoms have been identified.
Since Oganesson is very unstable (with a half-life of about 0.89 milliseconds) and is not natural, there is almost no reason to consider its health hazards.
Heaviest element found in nature: Uranium
Uranium glass glowing under ultraviolet light 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 intriguing facts about uranium | A weakly radioactive metal
Uranium is mainly used as nuclear fuel to produce electricity in nuclear power stations.