And h is the half-life, in days, of the substance. a scientist has a 10-mg sample of a radioactive isotope. the isotope has a half-life of 8 days. after 16 days, how much of the radioactive isotope remains?

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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