The student wants to use nails made of different metals to see which type of nail makes the best electromagnet.
Which investigation should the student perform to determine which type
of nail makes the strongest electromagnet?
Oь
Ос
Od
Wrap each type of nail with a different number of coils of the same type of wire and record how many paper clips each nail picks
up.
Wrap each type of nail with 40 coils of the same type of wire and record how many paper clips each nail picks up.
Wrap as many coils as possible around each type of nail and record which type of nail can hold the most coils.
Wrap each type of nail with a different type of wire and record how many paper clips each nail picks up.

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.