Actinide - All actinides are radioactive and release energy upon radioactive decay. The most common natural actinides found on earth are uranium, thorium and synthetic produced plutonium. The are used in nuclear reactors and nuclear weapons. Actinium (Ac) - Has the atomic number 89. It is soft, silvery-white radioactive metal. It reacts rapidly with oxygen and the moisture in the air forming a white coating of actinium oxide that stops further oxidation. Actinium is found in uranium ore and one tonne of uranium ore contains about 0.2 milligrams of actinium. Thorium (Th) - Has the atomic number 90. It is a naturally occurring radioactive chemical element and produces a radioactive gas, radon-220. Thorium is estimated to be about three to four times more abundant than uranium in the Earth's crust. It used to be common to use thorium as a light source in gas mantles. Protactinium (Pa) - Has the atomic number 91. It is a dense, silvery-grey metal that readily reacts with oxygen, water vapor and inorganic acids. It is very scarce, highly radioactive and highly toxic so there are currently no uses for it other than scientific research. Uranium (U) - Has the atomic number 92. It is a silvery-white metallic chemical element. Uranium is weakly radioactive because of its unstable isotopes. It has the second highest atomic weight of the primordially occurring elements, lighter only than plutonium and its density is 70% higher than lead but not as dense as gold or tungsten. Neptunium (Np) - Has the atomic number 93. It is a radioactive silvery metal that tarnishes when exposed to air. It is created by bombarding uranium with neutrons in nuclear reactors. It is called neptunium because it is just after uranium in the periodic table which is named after the planet uranus and neptune is after uranus in the solar system. Plutonium (Pu) - Has the atomic number 94. It is a radioactive metal that is silvery-grey and tarnishes when exposed to air and forms a dull coating when oxidized. Plutonium is the heaviest primordial element by virtue of its most stable isotope, plutonium-244 which has a half-life of 80 million years. Americium (Am) - Has the atomic number 95. It is a rather soft transuranic radioactive chemical element with a silvery appearance. It is created by bombarding uranium or plutonium with neutrons in a nuclear reactor. When it was first discovered it was kept from the public until 1945, it was created in 1944. Curium (Cm) - Has the atomic number 96. It is a hard, dense metal that is a transuranic radioactive chemical element with a silvery appearance. It has a relatively high melting point and boiling point for an actinide. Curium readily oxidizes. When introduced into the human body it accumulates in the bones, lungs and liver where it promotes cancer. Berkelium (BK) - Has the atomic number 97. It is a soft, silvery-white, transuranic radioactive chemical element. It is named after the city of Berkeley, California, which is the location of the university that it was discovered at. Californium (Cf) - Has the atomic number 98. It is a silvery, radioactive chemical element and has the second highest atomic mass of all elements that have been made in large amounts (enough to see with the naked eye). Einsteinium (Es) - Has the atomic number 99. It was discovered in the debris of the first hydrogen bomb blast in 1952 and is named after Albert Einstein. Einsteinium is silvery, soft paramagnetic metal. Fermium (Fm) - Has the atomic number 100. Fermium is the heaviest element that can be formed by neutron bombardment of lighter elements and was discovered in the debris of the first hydrogen bomb blast and was named after Enrico Fermi who was one of the nuclear physics scientists. Mendelevium (Md) - Has the atomic number 101. It is a metallic radioactive transuranic and a synthetic element. It is created by bombarding einsteinium with alpha particles and is named after the creater of the periodic table, Dmitri Ivanovich Mendeleev. Nobelium (No) - Has the atomic number 102. It is a synthetic element also little is known about the element it as shown to be a form of a stable divalent ion in solutions. Lawrencium (Lr) - Has the atomic number 103. It is a radioactive synthetic chemical element and is the last element in the actinide category but is sometimes considered a transition metal.
Actinides
