A chemical element is a substance made up of only one type of atom, and distinguised by its atomic number (the number of protons in its nucleus). Common examples of elements are hydrogen, carbon, nitrogen, and oxygen.
In total, 117 Elements have been observed as of 2007, of which 94 occur naturally on Earth. Some elements may also be called minerals if they are commonly found in soil and rocks. All chemical matter consists of these elements. New elements of higher atomic number are discovered from time to time, as products of artificial nuclear reactions.
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