A sample of an iron oxide weighing 0.982 g is found to contain 0.763 g of iron. The rest of the mass is oxygen. Determine the empirical formula of the compound.

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?