What is Uranium?

Uranium has always been an element often discussed about. Here we will study about the importance of uranium and what is uranium. Uranium is a chemical element which has its symbol as 'U'.Uranium's atomic number is 92 which indicates it has 92 protons and 92 electrons,6 of which are valence electrons. Uranium owes its discovery to Martin Heinrich Klaproth who discovered it in 1789. It is a silvery-grey metal and belongs to the actinide series of the periodic table. Uranium is weakly radioactive, the reason being the instability of all its isotopes.Uranium-238 (146 neutrons) and Uranium-235 (143 neutrons) are its most common isotopes. Uranium's mass number is 238.02891.

Uranium Symbol

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Uranium in Periodic Table

Atomic number (Z)



It doesn't belong to a particular group.It belongs to a series.





Element Category


Electronic Configuration

[Rn] 5f3 6d1 7s2

Electron distribution in shells

2 8 18 32 21 9 2

Properties of Uranium

Atomic Properties


Pauling scale: 1.38

Ionization energies

1st: 597.6 kJ/mol

2nd: 1420 kJ/mol

Atomic radius

156 pm

Covalent radius

196 ± 7 pm

Chemical Properties

Melting point

1135°C, 2075°F, 1408 K

Boiling point

4131°C, 7468°F, 4404 K



Relative atomic mass


Key isotopes

235U, 238U

Here are some points telling about how uranium reacts.

  1. Uranium reacts with almost all nonmetals and their compounds except noble gases and the reactivity increases with temperature.

  2. It is dissolved in hydrochloric and nitric acid but with non-oxidizing acids, it reacts slowly.

  3. It is extracted from ores chemically and converted to uranium dioxide or other usable forms in the industry.

  4. Finely divided uranium reacts with cold water.

  5. Uranium-235 was the first isotope to be found fissile. When bombarded with slow neutrons it divides into two smaller nuclei mostly, releasing nuclear binding energy and more neutrons.

Physical Properties

  1. Uranium's physical state is solid at standard temperature and pressure.

  2. Its crystal structure is orthorhombic.

  3. The slow radioactive decay of uranium provides a major source of heat within the Earth, responsible for continental and convection drift.

  4. This element is 18.7 times denser than water.

  5. It is one of the heaviest naturally occurring elements when arranged according to the mass number.

  6. Due to the high density of uranium, it finds its use in counterweights of aircraft control surfaces and radiation shielding.

  7. It is malleable, ductile, slightly paramagnetic, strongly electropositive and a poor electrical conductor.

  8. Naturally it is found as a mixture of two isotopes which are slightly different forms namely U-238 accounting for 99.3% and U-235 as 0.7%.

  9. It is silvery grey in natural appearance.

  10. It corrodes to black oxide coat in the air.

Uranium Uses

Uranium is an important element. Here we will know about its applications and what is uranium used for.

  1. U-235 is essential because of the process of nuclear fission which releases a lot of energy.

  2. In the military sector, it finds its major use in high-density penetrators.

  3. Depleted uranium plates can be used to harden tank armours and other removable vehicle armour.

  4. Depleted uranium is also used as a shielding material in some of the containers used to store and transport radioactive materials.

  5. Used as counterweights for aircraft control surfaces.

  6. Also used as ballast for missile re-entry vehicles and as a shielding material.

  7. Its high density makes its use possible in inertial guidance systems and gyroscopic compasses.

  8. Uranium-235 has been used in wars as fissile explosive material to produce a nuclear weapon.

  9. One of the important uses of uranium is as the thermal power source used in nuclear power plants.

  10. Its importance can be determined by the fact that theoretically, energy produced by the burning of 1.5 million kilograms of coal can be produced by 1 kilogram of U-235 assuming complete fission.

  11. Radium is extracted from uranium.

  12. Uranium found its use in photographic chemicals and in lamp filaments.

  13. In leather and wood industries for stains and dyes.

  14. In transmission electron microscopy as electron dense stains.

  15. Uranium is also used for different kinds of dating.

  16. In the making of high energy X-rays, it is used as X-ray targets.

Uranium Facts

  1. This element's name is taken from the planet Uranus.

  2. It is the heaviest naturally occurring element in the universe.

  3. It is highly unstable.

  4. Practically it is infinite as a power source.

  5. It is quite harmful to kidneys if ingested in a bigger amount.

  6. It is devastating for mankind as a bomb and even the after radiations lead to severe consequences.

FAQ (Frequently Asked Questions)

1) How is the Presence of Uranium Tested in Water?

It is shown in studies that elevated levels of uranium from any source, including drinking water, can increase a person's risk of kidney damage. The kidney is most prone to be damaged by uranium and overtime it increases the risk of cancer as well. Solid fluorimetry is used to measure Uranium in water. It can be done either by laser excitation or ultraviolet light following fusion of the sample with a pellet of carbonate and sodium fluoride (detection limit 0.1 µg/litre). Reverse osmosis method is used to remove uranium from water.

2) What Group is Uranium in?

Uranium doesn't belong to a particular numbered group of periodic table like 6th or 7th, rather it belongs to a series or family of elements known as actinide series or actinide family.This series is in the f-block and 7th period of the periodic table after the 2nd group. Actinide series includes elements from atomic number 89-103, consisting actinium (atomic number-89) as its first member from which the name of the series comes. So uranium with atomic number 92 is the 4th element of this series.Elements of this series are called actinides and all of them are radioactive which release energy on radioactive decay.