Which of the following is correct when writing formulas for ionic compounds? A. Put the nonmetal first, followed by the metal.
B. The charge of the ions is equal to the subscript for that ion.
C. The compound needs to be net neutral.
D. Put all polyatomic ions in parentheses.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.