Copper atomic energy levels

Inasmuch as the inscribed sphere corresponds to only 226 electrons per unit cube, it seems likely that the density of energy levels in momentum space has become small at 250.88, possibly small enough to provide a satisfactory explanation of the filled-zone properties. However, there exists the possibility that the Brillouin polyhedron is in fact completely filled by valence electrons. If there are 255.6 valence electrons per 52 atoms at the composition Cu6Zn8, and if the valence of copper is one greater than the valence of zinc, then it is possible to determine values of the metallic valences of these elements from the assumption that the Brillouin polyhedron is filled. These values are found to be 5.53 for copper and 4.53 for zinc. The accuracy of the determination of the metallic valences... 

The P-P band is ahrnys filled, corresponding 10 a P—P bond (225 pm) in the copper compound. At the other extreme, the P-P band it also filled, giving an antibonding interaction in addition. Thus, overall, there is a nonhonded interaction between the two phosphorus atoms and so we should not be surprised that the P-P distance is approximately twice the van der Waats radius or phosphorus (2 x 185 pm 384 pm) We can view the progression from Mn to Cu as a redox tuning of the occupancy of these energy levels 38... 

In the potassium row, the unoccupied 3d level begins to be filled its energy has dropped more slowly than that of the 3s and 3p levels, but it becomes filled before the 4p level begins to fill then in the ground state of scandium the 3d level becomes occupied with one electron. Elements in which some d states are occupied arc called transition metals. The 3d states have become completely filled when copper, atomic number 29, is reached. The 3d states become part of the atomic core as Z increases further, and the series Cu, Zn, Ga,..., gains electrons in an order similar to that of the series Na, Mg, Al,. ... 

Figure 4.2 Energy levels in a copper atom (after Siegbahn 1%7 in J.P. Eberhart, M thodes physiques d tude des mineraux et des mat -riaux soIides Doin, 1976).

Most of these elements have got two electrons in their outermost level, and you know that it is the electrons in the outermost level that determine properties such as oxidation number. In fact, these elements do have very similar properties, but one of those properties is that they don t have a fixed oxidation number. You might expect most of them to have an oxidation number of +2 because there are two electrons in their outer shells. In fact, these elements can very easily shift electrons between the third and fourth energy levels. If you look at copper, for example, you would expect it to have an oxidation number of +1, and it does - in some of its compounds. If a copper atom lets one of the electrons from its third level rise to the fourth level, however, and then loses both these electrons, it will form ions with a double positive charge, i.e. its oxidation number will be +2 in some of its compounds. 

---