Resonance structure

[votruong]

I have a question about the formic acid resonance structures. Please look at the attachment for the question and let me know what your answer is and why. Thanks in advance

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[lutopie0730]

It is already in order i think

First one has no charge separation so it is the most stable one
Second one has charge but every atom obeys octet rule
Third one and the last one do not have octet but still the third one is more stable than the last one because it has negative charge on oxygen, which is more electronegative than carbon

 

[ktran17]

I think its

I>III>II>IV

 

[kl352]

I > III > II > IV

positive charge on carbon, negative charge on oxygen should be more stable than positive and negative on both oxygens

 

[ikecarus]

I, III, II, IV

I: No charges, so most stable
III: Negative charge on oxygen and positive charge on carbon are preferred to the charges assigned in II and IV
II: You should avoid having a positive charge on oxygen, but this is slightly better than having a negative charge on carbon
IV: You should never have a negative charge on carbon

 

[votruong]

According to the solution, the answer is (i)>(ii)>(iii)>(iv) and the explanation is because (i) and (ii) have more covalent bonds than (iii) and (iv). I don't like how they explained but after reading lutopie0730 response, I looked it in my book and it does say "resonance structures in which every atom has an octet are more stable", so the answer is (i)>(ii)>(iii)>(iv) Thanks for everybody's help.