Classify each as a lewis acid or lewis base...
A)H20
B)O2-
C)Cu2+
D)SO3
E)AlCl3
Lewis acids are electron pair acceptors.
Lewis bases are electron pair donors.
Look at H2O, for example.
  ..
H:O:
  ..
  H
This molecule has no "holes" to accept an electron. Would you expect this to be an acid or a base by Lewis standards?
I think it would be a base because like you said it has no space to accept any electrons. As, for the other compounds is this correct:
O2- is a lewis base
Cu2+ is a lewis base
AlCl3 is an acid
SO3 is an acid
????
Apparently my response didn't post. I think Cu^+2 will be a Lewis acid. It wants to accept electrons to make that Cu(s).
To determine whether a substance is a Lewis acid or a Lewis base, we need to understand the concept of Lewis acids and Lewis bases.
A Lewis acid is a species that can accept an electron pair, while a Lewis base is a species that can donate an electron pair. In other words, a Lewis acid is an electron pair acceptor, while a Lewis base is an electron pair donor.
Now, let's classify each of the given substances as Lewis acids or Lewis bases:
A) H2O (water):
Water is a Lewis base because it has a lone pair of electrons on the oxygen atom, which it can donate to form a coordinate bond with a Lewis acid.
B) O2- (oxide ion):
The oxide ion (O2-) is a Lewis base because it can donate its extra pair of electrons to form a coordinate bond with a Lewis acid.
C) Cu2+ (copper ion):
The copper ion (Cu2+) is a Lewis acid because it can accept a pair of electrons from a Lewis base to form a coordinate bond.
D) SO3 (sulfur trioxide):
Sulfur trioxide (SO3) is a Lewis acid because the central sulfur atom can accept a pair of electrons from a Lewis base.
E) AlCl3 (aluminum chloride):
Aluminum chloride (AlCl3) is a Lewis acid because the aluminum atom can accept a pair of electrons from a Lewis base.
In summary:
- H2O is a Lewis base.
- O2- is a Lewis base.
- Cu2+ is a Lewis acid.
- SO3 is a Lewis acid.
- AlCl3 is a Lewis acid.