What Is Uranium? Atomic Structure, Reactivity, and Everyday Uses Explained
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
Properties of Uranium
Atomic Properties
Chemical Properties
Here are some points telling about how uranium reacts.
Uranium reacts with almost all nonmetals and their compounds except noble gases and the reactivity increases with temperature.
It is dissolved in hydrochloric and nitric acid but with non-oxidizing acids, it reacts slowly.
It is extracted from ores chemically and converted to uranium dioxide or other usable forms in the industry.
Finely divided uranium reacts with cold water.
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
Uranium's physical state is solid at standard temperature and pressure.
Its crystal structure is orthorhombic.
The slow radioactive decay of uranium provides a major source of heat within the Earth, responsible for continental and convection drift.
This element is 18.7 times denser than water.
It is one of the heaviest naturally occurring elements when arranged according to the mass number.
Due to the high density of uranium, it finds its use in counterweights of aircraft control surfaces and radiation shielding.
It is malleable, ductile, slightly paramagnetic, strongly electropositive and a poor electrical conductor.
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%.
It is silvery grey in natural appearance.
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.
U-235 is essential because of the process of nuclear fission which releases a lot of energy.
In the military sector, it finds its major use in high-density penetrators.
Depleted uranium plates can be used to harden tank armours and other removable vehicle armour.
Depleted uranium is also used as a shielding material in some of the containers used to store and transport radioactive materials.
Used as counterweights for aircraft control surfaces.
Also used as ballast for missile re-entry vehicles and as a shielding material.
Its high density makes its use possible in inertial guidance systems and gyroscopic compasses.
Uranium-235 has been used in wars as fissile explosive material to produce a nuclear weapon.
One of the important uses of uranium is as the thermal power source used in nuclear power plants.
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.
Radium is extracted from uranium.
Uranium found its use in photographic chemicals and in lamp filaments.
In leather and wood industries for stains and dyes.
In transmission electron microscopy as electron dense stains.
Uranium is also used for different kinds of dating.
In the making of high energy X-rays, it is used as X-ray targets.
Uranium Facts
This element's name is taken from the planet Uranus.
It is the heaviest naturally occurring element in the universe.
It is highly unstable.
Practically it is infinite as a power source.
It is quite harmful to kidneys if ingested in a bigger amount.
It is devastating for mankind as a bomb and even the after radiations lead to severe consequences.
FAQs on Uranium: Chemistry, Properties & Applications
1. What is uranium and where is it found naturally?
Uranium is a silvery-grey, radioactive chemical element with the symbol U and atomic number 92. It is a member of the actinide series of the periodic table. Uranium is found naturally in low concentrations in soil, rock, and water. It is commercially extracted from uranium-bearing minerals such as uraninite (most commonly known as pitchblende).
2. What is the position of uranium in the periodic table?
Uranium is located in the f-block of the periodic table, specifically within the actinide series. It is in the 7th period. This series includes elements with atomic numbers from 89 (Actinium) to 103 (Lawrencium), all of which are radioactive.
3. What are the key physical and chemical properties of uranium?
Uranium has several distinct properties:
Physical Properties: It is a very dense, silvery-white, malleable, and ductile metal. It has three crystalline modifications (allotropes) and is paramagnetic.
Chemical Properties: Uranium is highly reactive. It tarnishes in air, forming a dark layer of uranium oxide. It reacts with almost all non-metallic elements and their compounds. It dissolves in acids but is not attacked by alkalis.
4. What are the most important applications of uranium?
The primary application of uranium is as a fuel for nuclear power plants to generate electricity. Other significant uses include:
Production of medical isotopes used for diagnosis and cancer therapy.
Powering naval submarines and aircraft carriers.
Use as a dense material for counterweights in aircraft and as radiation shielding.
Creation of fissile materials like plutonium for military applications.
5. What makes uranium radioactive, and what are its main isotopes?
Uranium is radioactive because its nucleus is unstable. The large number of protons and neutrons in its nucleus results in significant repulsive forces that the strong nuclear force cannot permanently contain. This instability leads to radioactive decay, where the atom releases energy and particles. The most important natural isotopes are:
Uranium-238 (238U): Makes up over 99% of natural uranium. It is fertile, meaning it can be converted to fissile plutonium-239.
Uranium-235 (235U): The key fissile isotope, making up about 0.72% of natural uranium. It is crucial for sustaining a chain reaction in most nuclear reactors.
6. What is uranium enrichment and why is it necessary for certain applications?
Uranium enrichment is the process of increasing the concentration of the fissile isotope 235U beyond its natural abundance of 0.72%. This process is essential because most commercial nuclear power reactors require fuel with 3% to 5% 235U to efficiently sustain a controlled nuclear chain reaction. Without enrichment, the concentration of fissile atoms is too low to generate heat effectively in these common reactor designs.
7. Why is uranium considered a health hazard?
Uranium poses two distinct health risks. First, it exhibits chemical toxicity similar to other heavy metals like lead and mercury. If ingested or inhaled, it can cause severe damage to the kidneys. Second, it presents a radiological risk. As a radioactive element, it and its decay products emit ionising radiation (primarily alpha particles) that can damage DNA and increase the long-term risk of cancer.
8. What are the common oxidation states of uranium in its compounds?
Uranium is chemically versatile and exhibits several oxidation states, typically from +3 to +6. The most common and stable oxidation states found in its compounds are +4 (uranous) and +6 (uranyl). The +6 state is particularly stable and frequently forms the linear uranyl ion, UO₂²⁺, which is a common species in aqueous solutions and many solid compounds.
