Adds electron configuration to rhenium

elements/rhenium.md

@@ -5,6 +5,9 @@ title : Rhenium
 
 Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. Rhenium has the third-highest melting point and highest boiling point of any stable element at 5903 K. Rhenium resembles manganese and technetium chemically and is mainly obtained as a by-product of the extraction and refinement of molybdenum and copper ores. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7.
 
+Electron configuration	[Xe] 4f14 5d5 6s2
+
 Wikipedia contributors. (2019, May 31). Rhenium. In Wikipedia, The Free Encyclopedia. Retrieved 19:28, July 23, 2019, from https://en.wikipedia.org/w/index.php?title=Rhenium&oldid=899621753
 
 
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