When electrons are added is it positive or negative

Negative because electrons are a nagative charge

I guess what you mean is when electrons are gained by a particular atom, does it become negative or positive?
It becomes negative. This is because the no. of elections are greater than the no of protons.
If it had lost electrons if would've been positive as the no. of protons are now greater the no. of electrons.
Hope this helps.

The answers are 3.c kelvin4.b liquids only