The components of a mixture may be separated based on the physical properties of:

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.

Iwould you figure it out but you don't have a picture or in your question as to what the physical property you're looking for is

Matter- occupies space and possesses rest massno matter is the opposite