汞(Hg)的核外电子排布是1s22s22p63s23p63d104s24p64d105s25p64f145d106s2还是1s22s22p63s23p63d104s24p64d104f145s25p65d106s2 ?若失去外层电子是先从6s->5d->4f能级失去还是6s->5d->5p ?