Which change of phase is exothermic? A H
H2S(g) → H2S(1)
B. CO2(s) CO2().
C
H2O(s) –H2O(g)
D. NH3(1) NH3(9)

10 years is the answer

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!

if you need further assistance, let me know: )

~ trueboss72

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