English UK. This law, however, is justified in the periodic table for second row elements whose outermost-shell capacity is 8 electrons. For the outer valence electrons of a carbon atom, the electrons are found in the 2p orbital. Many different models have been proposed throughout the history of quantum mechanics , but the most prominent system of nomenclature spawned from the Hund-Mulliken molecular orbital theory of Friedrich Hund , Robert S. Answer The Pauli exclusion principle states that no two electrons can have the same four quantum numbers. Electrons are added to a subshell with the same value of the spin quantum number until each orbital in the subshell has at least one electron.