Question

why are noble gas included under non metals
​

Answer 1

noble gases show all properties of non metals like non ductile, non malleable, low melting point, etc.

Hope this helps you mate.

Answer 2

Because the outermost electron shell of atom of these gases is full, they do not react chemically with other substances except under certain special conditions .Noble gases are known as inert gas.The noble gases are not reactive. This is because they have little tendency to gain or lose electrons.