gas 4d

1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 3 The reason why this electron configuration seems more complex is that the f-block, the Lanthanide series, is involved. 4d sgp toto Most students who first learn electron configurations often have trouble with configurations that must pass through the f-block because they often