This is the most basic and not difficult to master. Work hard!
The above (1) is an exclamatory sentence, so it is not a proposition. (3) It is a question, not a problem. (4) It is an imperative sentence, not an imperative sentence. (6) It is an exclamatory sentence, not an exclamatory sentence. 13 is an expression, not a declarative sentence, andno. (17) is an imperative sentence, not a sentence.
In a word: (1) (3) (4) (6) (13) (17) is not a proposition. The rest are propositions.
One thing to note here is that the proposition is not necessarily right or wrong. As mentioned above, (12) is a wrong proposition.