What is the different between charge +2 and 2+ ?

What neutral atom is isoelectronic to mn+4

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?

Which type of precipitation would most likely form when the surface air temperature is slightly below freezing and the air temperature increases as you move upward away from the ground?