6. Which ion is written first in an ionic compound? Second? 7. When are parentheses used in ionic compound formulas?
8. What type of bond is between :Jodium and chlorine in sodium chloride
(NaCl)?
9. What type of bond is between carbon and oxygen in carbon monoxide
(CO)?

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