A100 gram sample of radium-226 has a half life of 1,600 years. how long will it take before before there are only 12.5 grams of the radioactive radium-226 remaining

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.

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