by the room number
haven't you looked at the maps?... everything wit an L in the room name is on North campus, everything with an E in the room name is on the main campus (ther eis no such thing as the 'south' campus - it's just parra campus.. and the other is "parra north" so if you ask about the "south" campus people may look at you confused
)
there is not general rule as to what is at what campus for non-science-y courses..
other units that are at parra north are there due to an inability to fit in rooms at the main campus so it just depends... also, not all classes in the one unit will be at parra nth just coz one is