This is the OH- Lewis structure.
We have 6 valence electrons for the Oxygen,
plus one for the Hydrogen, and this negative
sign up here means we have an additional electron
for a total of 8 valence electrons for the
OH- Lewis structure.
Put our Oxygen right here, and next to it,
we'll put a Hydrogen.
We have 8 valence electrons for the OH- Lewis
structure.
We'll put 2 between the Hydrogen and Oxygen
to form a chemical bond.
We'll go around the Oxygen to complete its
octet: 4, 6, and 8.
So at this point, the Hydrogen has two valence
electrons, so it has a full outer shell; and
the Oxygen, it needs eight for an octet, and
it has eight.
And we're still only using the eight valence
electrons we have for the OH- Lewis structure.
One last thing: we do need to put brackets
around it and a negative sign to show that
it's an ion.
So that's it: that's the Lewis structure for
OH-.
This is Dr. B., and thanks for watching.
