In addition to showing the ratio of atoms in a molecule, what else do the subscripts in a formula tell us?

In addition to showing the ratio of atoms in a molecule,the subscripts in a formula tells us other basic and vital facts like, chemical formulas being represented make use of chemical species like compounds and ions using numbers and letters.

The number that appear as subscripts in the chemical formula only show the number of the atoms of the element directly and immediately before the subscript. one atom of that element is present if no subscript appears.

what is the volume occupied by 40 grams of argon gas (ar) at standard conditions? what volume, in liters, is occupied by 1.5 x 1023 

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.