Manganese
Manganese, the 25th element, is reddish gray or silvery, and is brittle and
metallic.It has an atomic mass of 54.938 amu, and a specific gravity of 7.44.
It's electron levels are 2-8-13-2, and it is in group 7B. It has valences of
+4, 2, 7, 6, and 3. Mn was discovered in 1774 by Johan Gahn of Sweded. Mn
melts at 1244.85 degrees C, and boils at 1961.85 degrees C. It is the cause of
black sand on most nonvolcanic beaches. Exposure to manganese can cause permanent brain
damage, poor appetite, weakness, sleepiness, changes in speech, balance, and personality, as
well as chills, fever, aching, chest congestion, lung allergies, and damage to the kidneys and
liver.
May 21, 1997
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