Radicals

[Emily Glaser 1F]

How do we determine which element becomes the radical in a Lewis Structure when we already determined the Lewis Structure has a radical?

[Remi Lathrop 1G]

One good way to determine which element will accept the radical is to consider formal charge. If the radical will bring the center atom closer- or all the way to- a formal charge of 0 then it is most likely that the radical will go on that atom. You can also consider electronegativity because the more electronegative element will pull electrons toward it with more force and thus will be more likely to hold the radical.
However, formal charge is usually more important than electronegativity because the molecule wants to be as stable as possible.

[welcometochillis]

Another way to think about it is if the structure ends up having an odd number of valence electrons. or a single unpaired electron (which ever makes more sense to you) because of this it is more unstable and therefore radical.

[Madeline Musselman 3H]

The easiest way to determine if a substance is a radical is by adding the total number of valence electrons in the compound. If there is an even number it is NOT a radical, if it has an odd number it IS a radical. For example in HCl there are a total number of 8 valence electrons meaning that it is a non-radical. However, in HO there is total of only 7 valence electrons; therefore, HO is a radical.