How do the isotopes of Be-9 and Be-7 differ? A. Be-9 has 2 more electrons than Be-7.
B. Be-9 has 2 more protons than Be-7.
C. Be-9 has 2 more neutrons than Be-7.
D. There is no difference. They are exactly the same.

1. o2(g)as a product

It will appear as o2(g) as a reactant 

Answer    "a salt" would be the best answerexplanationsalts can be defined as ionic compounds that are neither acids nor bases. nacl is an example of a salt, and its ionic.an enzyme is an organic compound which is covalently bonded, not ionically bonded.acids are generally held together by covalent bondsan element does not need any bonds to exist

A. is your answer.  hope this