List of chemical elements

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A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. Here, the elements are ordered alphabetically. Each element is followed by its atomic number, the total number of protons in the atomic nucleus. (See also periodic table of the elements.)

Chemical compound

Print Cite Share MoreWRITTEN BYRichard O.C. NormanSee All ContributorsRector, Exeter College, University of Oxford. Professor of Chemistry, University of York, England, 1956–87. Author of Principles of Organic Synthesis.See Article History

Chemical compound, any substance composed of identical molecules consisting of atoms of two or more chemical elements.

Lawrencium – Lr

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Titles: Lr, element 103

Lawrencium (Lr), synthetic chemical element, the 14th member of the actinoid series of the periodic table, atomic number 103. Not occurring in nature, lawrencium (probably as the isotope lawrencium-257) was first produced (1961) by chemists Albert Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer at the University of California, Berkeley, by bombarding a mixture of the longest-lived isotopes of californium (atomic number 98) with boron ions (atomic number 5) accelerated in a heavy-ion linear accelerator. The element was named after American physicist Ernest O. Lawrence.

Nobelium – No

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Titles: No, element 102

Nobelium (No), synthetic chemical element of the actinoid series of the periodic table, atomic number 102. The element was named after Swedish chemist Alfred Nobel.

Mendelevium – Md

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Titles: Md, element 101

Mendelevium (Md), synthetic chemical element of the actinoid series of the periodic table, atomic number 101. It was the first element to be synthesized and discovered a few atoms at a time. Not occurring in nature, mendelevium (as the isotope mendelevium-256) was discovered (1955) by American chemists Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley G. Thompson, and Glenn T. Seaborg at the University of California, Berkeley, as a product resulting from the helium–ion (alpha-particle) bombardment of a minute quantity (about a billion atoms) of einsteinium-253 (atomic number 99). The element was named after Russian chemist Dmitry Mendeleyev.

Fermium – Fm

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Titles: Fm, element 100

Fermium (Fm), synthetic chemical element of the actinoid series of the periodic table, atomic number 100. Fermium (as the isotope fermium-255) is produced by the intense neutron irradiation of uranium-238 and was first positively identified by American chemist Albert Ghiorso and coworkers at Berkeley, California, in debris taken from the first thermonuclear (hydrogen bomb) test explosion (November 1952), “Mike,” in the South Pacific. The element was named after the Italian-born American physicist Enrico Fermi.

Einsteinium – Es

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Title: Es

Einsteinium (Es), synthetic chemical element of the actinoid series of the periodic table, atomic number 99. Not occurring in nature, einsteinium (as the isotope einsteinium-253) was first produced by intense neutron irradiation of uranium-238 during the detonation of nuclear weapons. This isotope was identified in December 1952 by Albert Ghiorso and coworkers at Berkeley, California, in debris taken from the first thermonuclear (hydrogen bomb) explosion, “Mike,” in the South Pacific (November 1952). The element was named after the German-born physicist Albert Einstein.

Californium – Cf

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Title: Cf

Californium (Cf), synthetic chemical element of the actinoid series of the periodic table, atomic number 98. Not occurring in nature, californium (as the isotope californium-245) was discovered (1950) by American chemists Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, as a product resulting from the helium–ion bombardment of curium-242 (atomic number 96) in the 152-cm (60-inch) cyclotron, followed by chemical separation from other elements by chromatography. The element was named after the state of California, where it was discovered.

Berkelium – Bk

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Title: Bk

Berkelium (Bk), synthetic chemical element of the actinoid series of the periodic table, atomic number 97. Not occurring in nature, berkelium (as the isotope berkelium-243) was discovered in December 1949 by American chemists Stanley G. Thompson, Albert Ghiorso, and Glenn T. Seaborg at the University of California, Berkeley, as a product resulting from the helium–ion (alpha-particle) bombardment of americium-241 (atomic number 95) in a 152-cm (60-inch) cyclotron. The element was named after the city of Berkeley, where it was discovered.

Curium – Cm

WRITTEN BYLester MorssAdjunct Professor, Department of Chemistry, University of Maryland, College Park, Maryland.See Article History

Alternative Title: Cm

Curium (Cm), synthetic chemical element of the actinoid series of the periodic table, atomic number 96. Unknown in nature, curium (as the isotope curium-242) was discovered (summer 1944) at the University of Chicago by American chemists Glenn T. Seaborg, Ralph A. James, and Albert Ghiorso in a sample of a plutonium isotope, plutonium-239, that had been bombarded by helium ions (alpha particles) in the 152-cm (60-inch) cyclotron at the University of California, Berkeley. It was the third transuranium element to be discovered. The element was named after French physicists Pierre and Marie Curie.