The Chemical Elements
Elements are the building blocks of nature. Water, for example, is a compound composed of two ingredients: hydrogen and oxygen elements. Each element is a pure substance that cannot be split up into any simpler pure substance.
The smallest particle of an element that can exist is an atom. An atom is made up of subatomic particles. The most important of these are protons, which have positive electrical charges; electrons, which have negative electrical charges; and neutrons, which are electrically neutral.
The atomic number of an element is the number of protons in one atom of the element. Each element has a different atomic number. For example, the atomic numbers of hydrogen and oxygen are 1 and 8, respectively.
Elements with atomic numbers 1 (hydrogen) to 92 (uranium) occur naturally on Earth. Those with atomic numbers 93 (neptunium) or greater are artificial. They have to be synthesized, or created by combining two or more elements with lower atomic numbers. Element 100 is named fermium. Elements with atomic numbers 101 and onwards are known as the transfermium elements. They are also known as heavy elements because their atoms have very large masses compared with atoms of hydrogen, the lightest of all elements.
The heaviest element synthesized to date is element 112. One atom of this element was synthesized by scientists at the Heavy-Ion Research Center (Gesellschaft fr Schwerionenforschung [GSI]) in Darmstadt, Germany, in February 1996. It was made by bombarding the element lead (atomic number 82) with a high-energy beam of atoms of the element zinc (atomic number 30). The atom existed for a fraction of a second before splitting up. Elements 110 and 111 were discovered by the same group of scientists in 1994.
Names for the six new ?heavy? elements were approved on August 31, 1997, by the International Union of Pure and Applied Chemistry (IUPAC) in Geneva. Elements 110, 111, and 112 have not yet been named.