Question 6
What does 58.5 g of sodium chloride contain? (Formula mass: NaCl = 58.5)
The right answer is the one marked above.
6.022 × 1023 formula units. The same rule holds for an ionic compound: the formula mass in grams gives L formula units.
Ionic compounds have no molecules, so we do not say "molecules" — but the count is unchanged. Atoms, molecules or formula units, the number is the same.