<P> The Madelung energy ordering rule applies only to neutral atoms in their ground state . There are 10 elements among the transition metals and 9 elements among the lanthanoids and actinoids for which the Madelung rule predicts an electron configuration that differs from that determined experimentally by one electron orbit (in the case of palladium and thorium by two electron orbits). </P> <P> Exceptions to the Madelung rule in the transition metals: </P> <P> The valence d - subshell "borrows" one electron (in the case of palladium two electrons) from the valence s - subshell . </P> <Table> <Tr> <Th> Atom </Th> <Th> Cr </Th> <Th> Cu </Th> <Th> Nb </Th> <Th> Mo </Th> <Th> Ru </Th> <Th> Rh </Th> <Th> Pd </Th> <Th> Ag </Th> <Th> Pt </Th> <Th> Au </Th> </Tr> <Tr> <Td> Core electrons </Td> <Td> (Ar) </Td> <Td> (Ar) </Td> <Td> (Kr) </Td> <Td> (Kr) </Td> <Td> (Kr) </Td> <Td> (Kr) </Td> <Td> (Kr) </Td> <Td> (Kr) </Td> <Td> (Xe) </Td> <Td> (Xe) </Td> </Tr> <Tr> <Td> Madelung Rule </Td> <Td> 4s 3d </Td> <Td> 4s 3d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 6s 4f 5d </Td> <Td> 6s 4f 5d </Td> </Tr> <Tr> <Td> Experiment </Td> <Td> 4s 3d </Td> <Td> 4s 3d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 5s 4d </Td> <Td> 4d </Td> <Td> 5s 4d </Td> <Td> 6s 4f 5d </Td> <Td> 6s 4f 5d </Td> </Tr> </Table>

Which orbitals (s p d f) do the transition metals and lanthanoids and actinoids apply to