Classroom rules - broadly used term is правила поведения в школе (lit. school behaviour rules, implying classroom rules too), or правила поведения в классе - this makes sense too. Hence classroom expectations - can be translated as правила поведения в классе.

disruptive student - ученик с плохим поведением. Make sure you get the idea that AmEngl 'student' corresponds to Russian ученик (ученица) from elementary to high school, but it's студент/студентка if it's some college or university ABOVE high school.
She is mean! - one of the examples that's difficult to translate into Russian. Roughly can be translated as Она злая - but sounds a bit childish. Or you can say Я ей не нравлюсь (she doesn't like me, she's mean to ME).