The periodic table has a variety of different elements. Of the 118 elements, 95 are considered metals. I would venture to guess that, chemists aside, most of us might struggle to name more than 10 of them! Each metal has its own values for a range of different properties.
What are the 10 heaviest metals, by density and atomic weight, from lightest to heaviest?
| 10 of the Densest Metals | 10 of the Heaviest Metals |
| Mercury 13.546 g/cm^3 | Mercury 200.59 u |
| Americium 13.67 g/cm^3 | Lead 207.2 u. |
| Uranium 18.95 g/cm^3 | Astatine 210 u |
| Gold 19.32 g/cm^3 | Francium 223 u |
| Tungsten 19.35 g/cm^3 | Radium 226 u |
| Plutonium 19.84 g/cm^3 | Actinium 227 u |
| Neptunium 20.2 g/cm^3 | Protactinium 231.0359 u |
| Platinum 21.45 g/cm^3 | Thorium 232.037 u |
| Iridium 22.4 g/cm^3 | Uranium 238.028 u |
| Osmium 22.6 g/cm^3 | Plutonium 244 u |
Some of these rankings may surprise you. Suchas, is lead really not one of the top 10 densest metals? It’s not. But it isone of the heaviest. Let’s talk about density, atomic weight and how differentmetals measure up.
Density vs. Atomic Weight
When discussing heavy metals, there are twodifferent factors that may seem fairly similar, density, and atomic weight.They’re different measurements and are measured in different units.
Density is themass per unit volume. Density is measured in grams per cubic centimeter(g/cm^3) or kilograms per cubic meter (kg/m^3)
The density of a metal affects howdifferent metals interact in different situations. Forexample, lots of metal types will sink in the water because metal has a higherdensity than water. And a few metals, such as potassium, will actually float inwater because they are less dense than water.
Atomic weight isdefined as the average mass of atoms of an element. Units of atomic weight aredimensionless and based on one-twelfth (0.0833) of the weight of a carbon-12atom in its ground state.
In other words, a carbon-12 atom has a valueof 12 atomic mass units. Atomic weight is known more commonly as relativeatomic mass to avoid confusion because atomic mass isn’t the same as atomicweight. Weight implies a force that is exerted inside a gravitationalfield, which is then measured by units of force such as newtons.
Now that we’ve differentiated between thesetwo properties let’s take a look at the 10 metals with the highest measures ofeach.
The 10 Densest Metals:
10. Mercury 13.546 g/cm^3
Mercury is a metal in liquid form at roomtemperature, often referred to as quicksilver for its silvery-white appearance.
Mercury is very heavy. It weighs 13.6 timesmore than water in equal volumes. To put it in perspective: iron, stone, andlead can float on its surface.
This metal is used most popularly inbarometers, thermometers, and other scientific instruments; it is very usefulin conducting electricity. And mercury vapor is used in:
- Streetlights
- Advertising signs
- Fluorescent lamps.
9. Americium 13.67 g/cm^3
Americium is not natural; it is a syntheticradioactive chemical element that was first produced by a research team inChicago during the Manhattan project.
This actinide metal is used in your averagehousehold smoke detector, by using a form of the metal called americium dioxideto ionize the radiation.
8. Uranium 18.95 g/cm^3
Uranium also has a silvery-grey appearance andis referred to as an actinide metal. Uranium is used most commonly in themilitary for high-density penetration weapons.
At high impact speed, these projectiles ofdepleted uranium and other alloys have such speed, hardness, and density thatthey can cause massive damage to armored targets. Armor plates on tanks arealso hardened with uranium depleted plated
7. Gold 19.32 g/cm^3
Everybody is familiar with the bright yellowmetal, but in its purest form, it will look slightly reddish yellow. Despiteits density, it is soft and malleable.
Gold is used in a lot of jewelry because ofthe softness of its pure form. Many times, it’s alloyed with other metals tochange the ductility and hardness. One of most important uses of gold is inelectronics; gold creates corrosion-free electrical connectors in electricaldevices like computers.
6. Tungsten 19.35 g/cm^3
A very rare metal the is mined naturally inthe Earth often found with many other elements and chemical compounds ratherthan isolated.
Tungsten is well known for its robustness, andthe high density makes it the perfect metal to use in counterweights, ballastkeels for yachts, and tail ballasts in commercial aircraft. Depleted uraniumcan also fulfill many of these uses, but the optimal element is tungsten.
5. Plutonium 19.84 g/cm^3
Plutonium is an actinide metal that has asilvery grey appearance that tarnishes and dulls when it becomes exposed tooxygen.
The isotope plutonium-238 emits a lot ofthermal energy and has a low level of gamma rays and neutron rays. This isotopeis an alpha emitter. It combines low penetration with high energy which means it needs little shielding.
Being able to make so much heat, it cangenerate a lot of electricity as well. The half-life of this isotope is about87.74 years which makes it a perfect power source for devices that need tofunction without maintenance for about an average human’s lifespan.
4. Neptunium 20.2 g/cm^3
This is a radioactive actinide metal that appearssilvery and also tarnishes when it’s exposed to the air. Neptunium can be foundaccumulating within commercial household ionization chamber smoke detectorsfrom decaying americium.
Neptunium is fissionable and can possibly beused as fuel in a nuclear weapon or fast neutron reactor. However, many believethat neptunium has never been used to make a weapon to this day.
3. Platinum 21.45 g/cm^3
A very dense, ductile, malleable, precious,unreactive transition metals that look silvery-white. Platinum is used in allsorts of processes:
- Vehicle emission control devices.
- Jewelry
- Chemical Production
- Electrical applications
- Hard disk drives
Platinum is very resistant to wear and tear,and very tough all around. All the devices, appliances, and jewelry it’s usedin have a spectacular lifespan. Platinum is very rare and expensive, however.
2. Iridium 22.4 g/cm^3
A brittle, hard, transition metal that shareda silvery-white appearance with platinum, iridium is the second densest metalfollowing osmium.
Iridium is used primarily in electronics suchas spark plugs and electrodes. Devices that need to withstand against extremetemperatures are usually made of iridium.
1. Osmium 22.6 g/cm^3
Similar to Iridium, osmium is a hard-brittletransition metal that looks bluish-white. This element is the densest, beingfound in rarely in platinum ores it is a pretty scarce element
Osmium is used very rarely in its pure statebecause of its toxic and extremely volatile. Osmium is alloyed very often intodevices and machines that can need to withstand a lot of wear and tear.
Some other specific tools they are used inare:
- Instrument pivots
- Fountain Pens
- Electrical contacts
- Photograph style tips
The 10 Heaviest Metals
10. Mercury 200.59 u
Mercury is very heavy, along with its highdensity. It is used as a primary explosive and used in the cartridges offirearms.
The weight comes into play mostly when mercuryis in its liquid state because many things can float on top of it. The Fresnellenses of lighthouses in the past were put on top of the baths of mercury sothat they could float and rotate. This essentially acted like a bearing.
9. Lead 207.2 u
A very heavy metal that is still denser thanmany other materials. Lead is soft and malleable with a silvery look and slightshades of blue when first cut. Lead turns to a dull gray color once it’sexposed to air.
For many years lead was used as bullets duringthe middle ages because it was cheap and had a low melting point, allowingfaster casting with less equipment. Nowadays, it’s used in ballast keels onsailboats. The density helps it use a small volume while still providing waterresistance.
8. Astatine 210 u
Arguably, the rarest naturally occurring metalin the Earth’s crust this metalloid is surrounded with mystery. One of the mainstudies that have been ongoing for astatine-211 deals with its capabilities innuclear medicine. However, this requires fast work because its half-life isonly 7.2 hours.
Lead is very popular for construction as well.It’s used as a roofing material in the form of lead sheets to make flashing,cladding, and gutters.
7. Francium 223 u
Another radioactive element that is alsoclassified as an alkali metal. Francium is very rare and extremely unstable,which makes it very hard to use commercially. Francium has been used to searchfor cancer cures, but it was found not to be practical.
Francium can be synthesized, tapped, andcooled very easily, which makes it a great subject to explore spectroscopyexperiments.
6. Radium 226 u
An alkaline earth metal that lookssilvery-white in its pure form but black when exposed to oxygen.
Many uses for radium take advantage of itsradioactive properties. In industrial radiography, radium is a crucialradiation source.
5. Actinium 227 u
Usually considered the first transition metalin the 7th period, actinium is a silvery-white, soft radioactive metal. Thismetal reacts very fast to moisture and oxygen causing it to form a white coatthat prevents more oxidation
Actinium is very rare and expensive with avery high radioactivity level; with these factors in play, it doesn’t have alot of industrial applications. Research and study are where it is mostly usedfor alpha therapies and cancer treatment.
4. Protactinium 231.0359 u
A dense actinide metal that appearssilvery-gray and reacts very fast to oxygen, inorganic acids, and water vapor.
Proacting is between thorium and uranium onthe periodic table, but it still doesn’t have any industrial or commercialapplications. Protactinium is used only for research at this time.
3.Thorium 232.037 u
A very silvery metal that appears silver untilturning black when exposed to the air. This creates thorium dioxide on theouter layer, which becomes hard and malleable. Thorium’s radioactivity levelsare much weaker than other radioactive metals.
Many uses of thorium are related to itsdioxide other than the actual metal. This dioxide is special because it has avery high melting point so it can remain solid in flames and increase theflame’s brightness.
2.Uranium 238.028 u
Uranium is very similar to plutonium in termsof density, atomic weight, and their uses. Nuclear power plants are fueled byuranium; the fuel used is enriched at about 3% uranium.
1.Plutonium 244 u
Not only is plutonium very dense, but it has avery high atomic weight as well. Like uranium-235 plutonium can be used topropel submarines and aircraft carriers.