Arock contains 0.636 mg of 206pb for every 1.000 mg of 238u present. assuming that no lead was originally present, that all the 206pb formed over the years has remained in the rock, and that the number of nuclides in intermediate stages of decay between 238u and 206pb is negligible, calculate the age of the rock. (for 238u, t1/2 = 4.5 ✕ 109 years.)

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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