Noble gases, like helium (He), neon (Ne), and argon (Ar), possess a full outer electron shell.
What is included in the diagram
They follow the octet rule, having a stable configuration with their outermost shell containing the maximum number of electrons:
Helium: 2 electrons
Neon: 8 electrons
Argon: 8 electrons
In an electron dot diagram, each dot represents a valence electron. Noble gases have a complete valence shell, indicated by the full set of paired electrons or by eight dots surrounding the element symbol.
This stable configuration makes them unreactive because they neither gain nor lose electrons easily.
Their lack of reactivity and tendency not to form compounds stem from this stable electron configuration, as it requires substantial energy input to alter their stable state.