The left vertical scale in Fig. 2.13 gives density in g/mL. Label the scale to show freshwater, brackish water, seawater, and hypersaline water.

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass