Chemical element whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than 1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of a "pure element". In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the
Pyromorphite chemical tests. They were formerly confused under the names green lead ore and brown lead ore ("German: Grünbleierz and Braunbleierz"). The phosphate was first distinguished chemically by M. H. Klaproth in 1784, and it was named pyromorphite by J. F. L. Hausmann in 1813. The name is derived from the Greek for "pyr" (fire) and "morfe" (form) due to its crystallization behavior after being melted. "Paecilomyces javanicus" is a mold collected from a lead-polluted soil that is able to form biominerals of pyromorphite. The color of the mineral is usually some bright shade of green, yellow or brown, and the