Hund’s rules say that for terms with the same S and the same L, anda less than half filled subshell, the term with the lowest J is lowest in enegy, while a for more than half filled subshell, the term with the highest J is lowest. What if the subshell is exactly half-filled?

(A) Higest J is still lowest in energy.

(B) Lowest J is still lowest in energy.

(C) Hund’s rules are only for the ground state, and there is only one term with maximum S, so this problem doesn’t arise.

(D) Hund’s rules are empirical and therefore not stringent. This particular case must be decided by measurements.

Hund’s rules say that for terms with the same S and the same L, anda less than half filled subshell, the term with the lowest J is lowest in enegy, while a for more than half filled subshell, the term with the highest J is lowest. What if the subshell is exactly half-filled?

(A) Higest J is still lowest in energy.

(B) Lowest J is still lowest in energy.

(C) Hund’s rules are only for the ground state, and there is only one term with maximum S, so this problem doesn’t arise.

(D) Hund’s rules are empirical and therefore not stringent. This particular case must be decided by measurements.

Consider the magnetic moment due to orbital angular momentumof an electron:

Are alkali atoms in their ground states diamagnetic or paramagnetic?

1 B

(A) diamagnetic

(B) paramagnetic

Consider the magnetic moment due to orbital angular momentumof an electron:

Are alkali atoms in their ground states diamagnetic or paramagnetic?

1 B

(A) diamagnetic

(B) paramagnetic

Reason: The paramagnetism in alkali atoms comes from the spin magnetic moment, not the orbital magnetic moment.