In this letter, we propose a straightforward evaluation of atomic electronegativities within the framework of Bader's atoms-in-molecules theory, based on the basin decomposition of the molecular electronic chemical potential derived from the Kohn-Sham equations through the non-interacting kinetic energy. The use of such atomic descriptors for reactivity purposes is then illustrated on the prediction of the electrophilicity of carbon atoms in organic reagents. (C) 2015 Elsevier B.V. All rights reserved.