This is stoichiometry and i need part 2 and 3

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

Between 2014 and 2016, more than 25,000 children in flint, michigan, drank water that was contaminated with lead from lead pipes. during this time, the city claimed the water was safe to drink. which of these actions could the city have taken to ensure that the drinking water was free from lead?

Summarize possible ways in which phases of matter could combine to form a solution.