Elements in the first row (hydrogen and helium) will have outer electrons in the first energy level. Their principal quantum number is 1. Elements in the second row (lithium through neon) will have valence electrons in the second energy level with a principal quantum number of 2.The trend continues all the way down to the seventh row.nergy of Valence Electrons. Aside from the number of valence electrons an atom has, the energy they have (or the energy level that they are in) is the last bit of information that helps predict how an atom will react. Let's take one look at the first column of elements.