a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 28 percent of the atmosphere by volume; the most abundant element in the earth's crust
a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth''s crust
a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
