Answer:
3.02 X1023 atoms Ag limol. - - 0.50 1 moles. 6.02241023 atoms.
21 kg x [(3 x 35.45)/(12.01 + 19.00 + (3 x 35.45))] =
21 kg x (106.35/137.36) = 16.3 kg of chlorine
You just multiply the weight of the material by the fraction of chlorine (by weight). The others are done the same way
I think the answer is einsteinium is the heavier one here.
Na is the elemental abbreviation for sodium, and Cl is the abbreviation for chlorine.
When the two are combined, you get sodium-chloride, or table salt.
Hope that helped =)