The ground state of lithium (Z = 3) has two electrons in the 1s level and one in the 2s. Consider an excited state in which the outermost electron has been raised to the 3p level. Since the 3p wavefunctions are not very penetrating, you can estimate the energy of this electron by assuming it is completely outside both the other electrons. a. In this approximation what is the potential energy felt by the outermost electron?
b. In the same approximation write the formula for the energy of the outer electron if its principal quantum number is n.
c. Estimate the energy of the 3p electron in this way and compare with the observed value of −1.556 eV