Abstract

The statements and arguments based on experimental evidence used to support the claim that the 3d sub-level is below the 4s sub-level in scandium are examined. The flaw in all the arguments is that they assume the order in which the 3d and 4s sub-levels arrange remains the same in both the neutral atom and in its ions. Analysis of the ground and excited states of atomic spectra shows that as the number of electrons relative to the nuclear charge increases, the 3d level moves higher in energy relative to the 4s level. It is perfectly possible that in a neutral scandium atom the 3d sub-level is above the 4s sub-level and that when it ionizes the energy levels simultaneously rearrange during the process.