The simplest primary radical. A primary radical has only one non-H group attached (the methyl group in this case). Ethyl radical is more stable than methyl radical. Radicals are intrinsically electron-deficient species and the methyl group is a donor group capable of stabilizing the electron-deficient radical center. Note the conformation: The methyl group prefers to be in a conformation that aligns one of the C-H bonds with the p-AO of the radical center.