How does one recognize the highest occupied energy level? ?

If you are studying an element on the periodic table, look at which period/row it is in. With the S and P blocks of the periodic table, the period it's in is the same number as the valence energy level. but, if it is located in the D block, the valence energy level number is always one less than the period number the element is found in.

Olá. porque a reação na temperatura é muito rapida a do copo : )