Unpaired Electron Placement in Radicals

[Serene Liu 3H]

Textbook problem 2.61 asks you to draw the Lewis structure of HOCO, which is a radical. How do you know which element the unpaired electron goes on?

[505766240]

When you draw the lewis structure for HOCO, I believe the valence electrons for the two oxygens and one hydrogen should be filled already, so you only have C left to put the unpaired electron on.

[Sujin Lim 1H]

I think it was mentioned during one of my discussion sections that the unpaired electron for the radical should go on the less electronegative atom of the molecule (H atoms excluded). This is because the more electronegative atom will want to have more valence electrons, so they should have the paired electrons, whereas the less electronegative should have the unpaired (one less) electron. Hope this is correct!