posted by Twilight lover .
how can someone find out which element is a more chemically active nonmetal from looking at the Periodic Table? What element is a black crystal that hs 4 electrons in its outermost energy level?
The most active non-metals are to the upper right of the periodic table. Look at group 17 (VIIA) which would be fluorine. The black crystal probably is carbon. Look in group 14(IVA).[The most active metal is to the lower left.]