Symbol U
Atomic Number 92
Atomic Mass 238.029 g.mol 1
Discovered by Martin Heinrich Klaproth in 1789 

Chemical Properties of Uranium

Group Actinides Melting point 1135°C, 2075°F, 1408 K
Period 7 Boiling point 4131°C, 7468°F, 4404 K
Block f Density (g cm3) 19.1
Atomic number 92 Relative atomic mass 238.029
State at 20°C Solid Key isotopes 234U, 235U, 238U
Electron configuration [Rn] 5f36d17s2 CAS number 7440-61-1
ChemSpider ID 22425 ChemSpider is a free chemical structure database

What is Uranium?

  • Uranium is a weakly radioactive element with an atomic number 92 and symbol U in the periodic table.
  • Uranium is one of the heavy metals that can be utilized as a rich source of concentrated energy. The element exists in many rocks in the concentration of 2 to 4 ppm(parts per million) and common in Earth’s crust as tungsten and tin. It also exists in seawater and can be retrieved from the oceans.

Physical properties of Uranium

  • Uranium was formed over 6.6 billion years ago. Though it is not common in the solar system, its slow radioactive decay provides a major source of heat within the Earth, responsible for continental and convection drift.
  • Uranium’s high density means it also has applications in the counterweights of aircraft control surfaces and radiation shielding.
  • It is one of the heaviest among all the naturally occurring elements when arranged based on the increasing mass of their nuclei on a scale. The element is 18.7 times denser than water.
  • Uranium exists in various slightly different forms known as ‘isotopes.’ These isotopes are distinct in the number of uncharged particles in the nucleus.
  • Natural uranium was found as a mixture of two isotopes. U-238 accounts for 99.3% and U-235 around 0.7%.
  • Pure uranium is silver in color and readily oxidizes in air.
  • It is also used to color glass that glows greenish-yellow in black light, not due to radioactivity because the glass itself is a bit radioactive. The fluorescence is because of the UV light that excites the uranyl compound in the glass and makes it let off photons when it settles down.

Applications and effects of Uranium

  • The isotope U-235 is essential since it can be split readily and yield a lot of energy under certain conditions. Therefore it is known as ‘fissile’ and use the expression ‘nuclear fission.’
  • Uranium fission is made efficient by nuclear engineers. To increase the proportion of U-235, the engineers either gasify the element to differentiate the isotopes. According to studies, most enriched uranium in nuclear power plants is made up of 3-5% of U-235.

Certain Facts About Uranium

  • Uranium was named after the planet Uranus.

Practise This Question

State whether the following statement is True or False:
Suspension is a heterogeneous mixture.