A sample of rock contains 6.14 × 10^–4 g of Rb-87 and 3.51 × 10^–5 g of Sr-87. Calculate the age of the rock. (The half-life of the β decay of Rb-87 is 4.7 × 10^10 y.)

its first and third is your answer i did the qustion the fourth isnt right

2b2t

explanation:

2b2t

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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~ trueboss72

pv=nrt

explanation: