Draw the Lewis structures and determine which of these molecules has a central atom that violates the octet rule. Please note that NO3 has an odd number of electrons. But you must decide where the missing electron will be. Does the central atom violate the octet rule or do the oxygen atoms? Use formal charges to decide.
PCl3
BCl3
NO3-
XeF2
SO2
CS2
IF5
NH3
SO3

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.