The modern model of the atom describes electrons in a little less specific detail than earlier models did. why is it that being less sure about the placement of electrons in an atom is actually an improvement over earlier models?

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.