The first two electrons in lithium fill the 1s orbital and have the same sets of four what as the two electrons in helium?
kinetic numbers
decay numbers
gravity numbers
quantum numbers
The n = 1 shell is completely filled in a helium atom. The next atom is the alkali metal lithium with an atomic number of 3. The first two electrons in lithium fill the 1s orbital and have the same sets of four quantum numbers as the two electrons in helium. The remaining electron must occupy the orbital of next lowest energy, the 2s orbital (Figure 6.27 or Figure 6.28). Thus, the electron configuration and orbital diagram of lithium are:.