Question tags are the short questions that we put on the end of sentences – particularly in spoken English. There are lots of different question tags but the rules are not difficult to learn. The pronouns used in the question tags are the same pronouns that are used in the first part of the sentence, except for 'aren't I'. Actually, 'aren't I is not grammatically correct and 'am I not' is correct. I am a good student, am I not?................ [aren't I?] You are a good student, are you not?....... [aren't you?] He/she is a good student, is he/she not?.. [isn't he/she] We are good students, are we not?.......... [aren't we?] You are good students, are you not?........ [aren't you?] They are good students, are hey not?...... [aren't they?] Here's a good, simple explanation of question tags: http://learnenglish.britishcouncil.org/en/grammar-reference/question-tags

With regard to #2, "am I not" is correct. "Am not I" is incorrect. With regard to #1, this is a matter of opinion and a topic of debate! The short answer is: as long as you are in an English class, say "am I not?" but as soon as you get out into the real world, say "aren't I?" In real life, almost everyone says "aren't I," including well-educated careful speakers. "Am I not" is excessively correct, stilted, and pedantic. The problem is that there is no accepted contraction in English for "am I not." The American Heritage Dictionary's excellent usage note says: "The stigmatization of 'ain't' leaves us with no happy alternative for use in first-person questions. The widely used 'aren't I?,' though irregular, was found acceptable for use in speech by a majority of the Usage Panel as long ago as 1964, but in writing there is no acceptable substitute for the stilted 'am I not?'" #3 is correct. #4 is incorrect.

The only sentence that's wrong is the last one. You can't say "are I".

Question tags: The question tag for ‘I am’ is ‘aren’t I?’ “I’m the fastest, aren’t I?” - 1- I´m a good student, aren´t I? The negative form we use the same “am” form: “I’m not fat, am I?” - I´m not a good student, am I?