The noun subjects in your example full-form sentences are in the wrong location. A native English speaker would never say "is not it?", but rather "is it not?". The same goes for example 2 where the correct form would be "Are you not...."
The corrected subject-verb full-form versions can be a little awkward (when placed at the end of a sentence, this phrase structure feels particularly old fashioned), but they aren't wrong. I wouldn't even think twice if someone said "Are you not going to ____?" Meaning wise, there's no difference between your examples with and without the contractions.