in the electron cloud model the electron cloud in desner in some locations than others . what do the denser areas represent

Nuclear fusion is the source of energy for stars. besides hydrogen, which other element is most likely also common in stars?

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?

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?