Magnesium has 3 naturally occurring isotopes: mg (23.985 amu) with 78.99% abundance,
2 mg (24.986 amu) with 10.00% abundance, and a third with 11.01% abundance.
look up the atomic weight of magnesium, and then calculate the mass of the third isotope,

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.

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