The ground state electron configuration of aluminum is 1s² 2s²2p⁶ 3s² 3p¹
The ground state electron configuration of lithium is 1s² 2s¹
The ground state electron configuration of phosphorous is 1s² 2s²2p⁶ 3s² 3p³
The ground state electron configuration of scandium is 1s² 2s²2p⁶ 3s² 3p⁶3d¹ 4s²
In the ground state Al has 3 valence electrons, 2 electrons in the 3s orbital and 1 electron in the 3p orbital. The valence shell of Al is 3.
