An unknown element is a mixture of isotopes ¹⁵¹X (atomic mass = 150.99 amu) and ¹⁵³X (atomic mass = 153.03 amu). The average atomic mass of X is 151.36 amu. What is the percent abundance of ¹⁵³X?

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.

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