What does the number next to isotopes signify?

What are the concentrations of hydroxide and hydronium ions in a solution with a ph of 10.2?

This is a mixture that has the same composition throughout.

Will give brainliest it is a lab from k12 here is the linkfor each metal that participated in a chemical change, write the type of metal it is, based on your examination of the periodic table. type your answer here. (score for question 3: of 5 points) were there any metallic compounds that did not react with either the acid or the base? write the type of metal, based on your examination of the periodic table. type your answer here. (score for question 4: of 5 points) make a general statement about the reactivity of the metals in this experiment. type your answer here.