The elements that are found in the last column of the periodic table are an important group of elements that are called noble gases.
Those are helium, neon, argon, krypton, xenon, and radon.
A noble gas configuration consists of the elemental symbol of the last noble gas prior to that atom, followed by the configuration of the remaining electrons.
For example: for Mg, we make the substitution of [Ne] for the 1s22s22p6 part of the configuration. Magnesium's noble gas configuration becomes [Ne]3s2.