Ministry of Defence Main Building (United Kingdom) each and cost £12,600. Similar figures representing "air" and "fire" were intended to be installed at the south end of the building, however these were never constructed. During the 1950s, building staff nicknamed the statues "Mr and Mrs Parkinson", after Cyril Northcote Parkinson, the Board of Trade civil servant who devised Parkinson's Law which states "work expands so as to fill the time available for its completion". More recently MOD staff refer to the statues as the "two fat ladies". The badge of the RAF is carved into stone columns either side of the southern entrance to the building, reflecting
Aufbau principle the order of ionization of electrons in this and other transition metals far more intelligible, given that 4s electrons are invariably preferentially ionized. Aufbau principle The aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s shell is filled before the 2s subshell is occupied. In this way, the electrons of an atom or ion form the most stable electron configuration possible. An example is the configuration 1s 2s 2p 3s 3p for the phosphorus atom, meaning that the