What, roughly, is the volume of 18g of ice, and therefore what, roughly, is the volume of an ice molecule? If you
think of the molecule as a cube (yes this is a bad approximation), how big is that cube (how long are the sides of the cube)? Now do the same for an iron atom by considering solid iron, and for a lead atom by considering solid lead. Hint: Avogadro's number is the number 6.022 × 1023.