It's really tough to draw Lewis structures on these boards but here is a try. If it doesn't work I'll try to describe it.
 H +
 ..
:O:H
 ..
how do u set up the lewis structure for H30+?
i know the available electrons is 3 but it has a +1 so it makes ir 2??
7 answers
That looks pretty good to me EXCEPT that I left a H at the very bottom. Hope it helps.
You need to add an H to the bottom. No more electrons are necessary.
thank you but the set up for the total valance electrons is confusing?
i have this same homework problem
H3O+
H has 1 electron each x 2 atoms = 2 e
O has 6 electrons each x 1 atom = 6 e
Total of 8 electrons to be distributed.
Then a hydrogen ion (H+) with no electrons adds to either one of the two lone pairs of electrons of the oxygen atom. The completed structure looks like this.
 H  +
 ..
:O:H
 ..
 H
H has 1 electron each x 2 atoms = 2 e
O has 6 electrons each x 1 atom = 6 e
Total of 8 electrons to be distributed.
Then a hydrogen ion (H+) with no electrons adds to either one of the two lone pairs of electrons of the oxygen atom. The completed structure looks like this.
 H  +
 ..
:O:H
 ..
 H
This one looks ok to me.