Another atom of element Q has 8 neutrons. Compare this atom with the atom in Diagram 6.

They can measure  the amount of energy gained or lost

Your question is not clear but if you can explain yourself i would be glad to .  just trying to : ))

The closer the atoms are to becoming ionic the more highly dense the negatively charged side gets.

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.