I'm not sure but for the first one, if there were more electrons than protons that would mean the object would have a positive charge so you could put another object that is positively charged near it, to see if it would attract and if it would it would mean it's negatively charged and if it wouldn't it would mean it's positively charged. (not sure)
for the second one, after you've rubbed the balloon oh hair, the electrons from your hair have transferred onto the balloon, meaning that the balloon is now negatively charged. because the wall is neutral, it means that it has the SAME number of both protons and electrons ( positive and negative charges cancel out to create a neutral charge). because the protons are positively charged, and the balloon is negatively charged, the two objects will attract because opposite charges attract. this happens because of static electricity.
hope this helps :)
