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.

Ethene molecular fórmula= c2h4molecular weight = 29.046g/molhope it : )

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