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Bernard VALEUR: Engineer from the École supérieure de physique et de chimie industrielles de la Ville de Paris (ESPCI) - Doctor of Physical Sciences - Professor at the Conservatoire national des arts et métiers
INTRODUCTION
An element, in the chemical sense, is an entity common to the various varieties of a simple body, as well as to combinations of this body with others. An element's place in the periodic table is indicated by its atomic number, which represents the number of protons in the nucleus of an atom of that element. The atomic number also represents the number of electrons in an element's neutral atom. Isotope atoms of the same element have nuclei with the same number of protons, but differ in the number of neutrons. Isotopes (a Greek word meaning "same place") of the same element therefore occupy the same place in the periodic table. The sum of the number of protons and the number of neutrons is the mass number.
There are 93 naturally occurring elements, and a further 20 have been produced artificially, making a total of 113 elements with atomic numbers 1 to 112 and 114.
The main properties of the elements are presented in this article.
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Element properties
General properties
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