Answer:
CHO2- ion
Explanation:
We have the lewis structure of a formate-ion here
This is CHO2-.
The carbon atom is the central atom in the structure. It's the least electronegative atom (C). Carbon has 4 valence electrons. Oxygen has 6 valence electrons.
The carbon will bind with 1 hydrogen atom, this will form 1 single bond, because hydrogen has 1 valence electron.
The carbon will bind with oxygen via a double bond.
Since carbon has only 4 valence electrons, it can only form 1 bond with the other oxygen atom.
There will formed 1 double bond between C and O and 1 single bond between C and O resulting in a negative charged O-atom.
This means there are two resonance structures. for the CHO2- ion