4: The mass amount of protons and neutrons in an atom
We just covered this in my chem class
I believe its the first one because manganese is mn and IV is 4 but the cross thing thing will making it the second one but then you have to simplify making it the first one i hope that helps:)
The answer is 70 I guess. Hope this helps :)
That there was a dense positively charged center, what we call the nucleus now.
