Mavs04
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Hi so I’m a bit confused about compounds which have an overall charge - so are technically ionic, but contain covalent bonds between the atoms.

An example we did in class was Sodium hydroxide, specifically the hydroxide (OH-) bit. I get that the oxygen has gained an extra electron from elsewhere - the Na - to make it charged - so the negative charge lies on the oxygen atom.

What I’m confused about is how you can figure out which atom the charge lies on (which one has lost/gained extra electrons) if you’re only given the specific ion, like just the OH- part, is there a method to work it out?
Last edited by Mavs04; 4 weeks ago
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Pigster
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(Original post by Mavs04)
Hi so I’m a bit confused about compounds which have an overall charge - so are technically ionic, but contain covalent bonds between the atoms.

An example we did in class was Sodium hydroxide, specifically the hydroxide (OH-) bit. I get that the oxygen has gained an extra electron from elsewhere - the Na - to make it charged - so the negative charge lies on the oxygen atom.

What I’m confused about is how you can figure out which atom the charge lies on (which one has lost/gained extra electrons) if you’re only given the specific ion, like just the OH- part, is there a method to work it out?
It doesn't really matter on which atom the extra e- sits. What matters is that there is an extra e-.

In the case of OH-, you'd start with an O atom, with 6 e- in it's outer shell. You'd covalently bond it with an H atom (which has 1 e-) hence a shared pair where both atoms bring an e- to the bond. O still only has 7 e- and therefore the extra e- sits happily in O's outer shell, filling the octet.
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