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2016-02-01T00:24:17+05:30
Argon
its atomic no is 18
it is already stable
it is in 18th group of periodic table
they are less reactive
they undergo no chemical reaction
its valency is 0
it is a noble gas
it is derived from Greek which means 'lazy' or 'inactive'
2 5 2
2016-02-01T08:48:40+05:30
Helium is a noble gas having one shell and it has2 electrons
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