Test of RealQM vs StdQM: Reactivity of Gold

The electronic configuration for Gold Au is supposed to be 2 + 8 + 18 +  32 +  18 +  1 with a single electron in shell 6. Gold is very weakly reactive despite its single valence electron.

We compare with Sodium Na with configuration 2 + 8 + 1 with a single valence electron in shell 3. Sodium is highly reactive. Same for Lithium Li 2 + 1 and Potassium Ka 2 + 8 + 8 + 1.

What is the difference between Au and Li, Na and Ka, all with one single valence electron?

Standard Quantum Mechanics StdQM says that the weak reactivity of Gold is a relativistic effect coming from the 2 electrons in shell 1 moving at speed more the half the speed of light increasing the mass of the inner shell causing contraction of shell 6. This is a mind boggling explanation. To buy it requires a vivid fantasy. Physicists/chemists/scientists generally seek to come up with an explanation of some observed phenomenon rather than admitting that they have no clue, unless the phenomenon is of such grand scale that human understanding is beyond reach, like Big Bang. The weak reactivity of Gold has small scale and should be possible to understand. 

Let us compare the answer offered by RealQM. We then model a Gold atom Au as a +1 kernel surrounded by an electron which occupies a region around the kernel with distance bigger than R to the kernel representing all shells but the last. We seek to determine if two Au atoms can combine to form a molecule Au2 as a test of reactivity of Au. 

We run RealQM varying R and the distance between the two kernels using this code and get the following results for the energy E1 in Hartree (as minimal energy) at small distance D1 in atomic units and E2 as energy at large distance D2:

• R = 0     E1 =-1.17  at D1 = 1.4       E2 = -1     at  D2 = 4
• R = 0.5  E1 = -0.87  at D1 = 2         E2 = -0.85 at D2 = 4
• R = 1     E1 = -0.51  at D1 =2          E2 = - 0.63 at D2 =4

The case R = 0 corresponds to H2 with energy release 0.17 under formation of molecule.

The case R = 1 corresponds to Au2 which needs input of 0.12 to form.

The case R = 0.5 is intermediate with very small energy release 0.02.

The radius R increases with number of shells along with weakening of reactivity.   

We see that RealQM can explain the weak reactivity of Gold as an effect of increasing radius as an effect of increasing number of shells. To understand the essence of the argument, take a look at this output of RealQM for R = 1 at D1 = 2.1 showing the regions representing all the shells except the last, preventing accumulation of electron charge density between the kernels an so preventing chemical binding:

It is a simple picture, easy to understand and it has nothing to do with electrons inside atoms at relativistic speeds. The essence is that accumulation of charge density between the kernels (red) with binding effect is reduced with increasing R (white). 

PS RealQM in the above setting computes the 1st ionization energy of Gold to 0.33 Hartree in accordance with observation.