Here, "Satzklammer" just means that you should remember that the verb is in the 2nd position, except in i) where it comes first because it's a question. You have remembered, so don't worry about the "Satzklammer". :)
Everything is perfect, apart from j) where there is a typo: it should be "bringen" instead of "bringt".
As to your other question, in g) "gern" and "nachmittags" could change place without altering meaning/emphasis, also b) Er schreibt keine Postkarten im Urlaub; Er schreibt im Urlaub keine Postkarten (this would perhaps be the more frequently used word order) and f) Meine Mutter liest gern Bücher im Urlaub; Meine Mutter liest gern im Urlaub Bücher; Meine Mutter liest im Urlaub gern Bücher - all of these sentences would be perfectly correct. Therefore I recommend sticking to the rule you're being taught in class ;)