The noble gases are the elements in Group 0. They are chemically inert, which means they do not react with other elements under normal conditions. Their electronic configurations explain why.
Helium has two electrons, which completely fills its only shell. Neon has the electronic configuration 2,8 and argon has 2,8,8, so each of these atoms has eight electrons in its outer shell. In every noble gas the outer shell is full.
Atoms of other elements react to get a full outer shell, by gaining, losing or sharing electrons. A noble gas atom already has a full outer shell, so it has no need to gain, lose or share electrons. This makes it very stable and very unreactive compared with other elements. It is also why noble gases exist as single atoms rather than as molecules.
