Radical

[Ziyan Wang 3J]

Why can we say some species with odd number valence electrons are radicals? Is the converse-negative statement also true? (Does species with even pair of electrons necessarily mean that they are not radicals?)

[Daria Azizad 1K]

Species with an odd number of electrons have an unpaired electron. Take CH3 for example: there are 7 electrons total, so carbon will have 3 pairs and 1 single electron. This, by definition, makes it a radical. The converse is true, as even numbers of electrons form pairs.

[nickianel_4b]

Radicals are defined as compounds with an unpaired e-, and the converse is true--that compounds with an even number of electrons are not radicals. Important to note that because of the one unpaired e-, radicals are highly reactive and exist for only a short time (because they are likely to react and form something more stable).