複選題

55. Which of the following statements are true?
(A)an orbital can accommodate at most two electrons
(B)the electron density at a point is proportional to \( \psi^2 \) at that point
(C)the spin quantum number of an electron must be either +1/2 or -1/2
(D)a 2p orbital is more penetrating than a 2s; that is, it has a higher electron density near the nucleus and inside the charge cloud of a 1s orbital
(E)in the usual order of filling, the 6s orbital is filled before the 4f orbital