The noble gas configuration system helps to shorten the total electron configuration by using the symbol for the noble gas that lies before the particular element in the periodic table.
For example:
Na has atomic number 11
Electron configuration of Na: 1s2 2s2 2p6 3s1
Noble gas electron configuration of Na: [Ne] 3s1
Ne has atomic number 10 and lies before Na in the periodic table.
