Why the noble gases are found in small amounts in the earth's atmosphere?

They have completely filled outermost shell

Explanation:

The noble gases are the rarest and occur in trace amounts in the atmosphere because they have completely filled outermost and this makes them unreactive with other elements.

Elements become abundant as they combine with other species to form compounds.

Noble gases on the other hand have a high level of stability and do not readily combine with other species.

Some of these gases are :

        Helium

        Neon

        Argon

        Krypton

        Xenon

       Radon

They have very high ionization energy and very low electron affinity and so will not readily react.

i am going to put the answers in order i dint feel like typing it out so yeah

a

d

c

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a

d

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b

c

c

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d

50.23 i believe is correct but don't quote me on that.