A teacher has a beaker containing a mixture of iron filings (tiny pieces of iron) and sand. He challenges his class to develop a way to separate the iron filings and the sand.
Which method will separate the iron filings from the sand?
A. Add water to the mixture and stir well. Then let the water evaporate. The iron filings will be left behind.
B. Pass a magnet through the mixture. The iron filings will stick to the magnet. The sand will be left behind,
C. Shake the mixture until the iron filings rise to the top. Then scoop off the Iron filings. The sand will be left behind.
D. Add water to the mixture and stir well. Then pour it through a filter. Only the iron filings will go through the filter. The sand will be
left behind

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.

you need to have a picture of the atom that way we can answer it