Chapter 31, Problem 27PCE

(a)

To determine

The radius of the $n=4$ Bohr orbit of a doubly ionized lithium atom $\left({\text{Li}}^{2+},Z=3\right)$.

(b)

To determine

The energy required to raise an electron from $n=4$ state to $n=5$ state in ${\text{Li}}^{2+}$ and check whether this energy is greater than, less than, or equal to the energy required to raise an electron in hydrogen from the $n=4$ state to the $n=5$ state.

(c)

To determine

The calculation of relevant energies and verification of the answer to part (b).