Respuesta :
Hi, the answer is 13 , because the total of protons and neutrons together form the mass , in other words there are 6 protons and 7 neutrons , 6+7=13.
Mass number is 12.01g
What you do first to find is find how many protons it such as this atom has 6 so it going to be number 6 on the periodic table then find the mass
