MODELOS E ELETRONEGATIVIDADE: UMA PROPOSTA DE SEQUÊNCIA DIDÁTICA PARA O ENSINO DE QUÍMICA

Abstract

MODELS AND ELECTRONEGATIVITY: A PROPOSAL OF DIDACTIC SEQUENCE FOR CHEMISTRY TEACHING. Electronegativity is a useful chemical bonding property related to determining the polarity of molecules and formation of partial charges. In the 1930s, Linus Pauling studied the differences between theoretical and experimental binding energy values when he established that ionic contributions in covalent bonds were pertinent to elucidate these differences. The association of the nature of the elements present in the chemical bond with the discordance of results led to the quantitative determination of electronegativity, creating the first scale of this property. In addition, other scales were developed, such as by Robert Mulliken (1934), Albert Allred and Eugene Rochow (1958) and Leland Allen (1989). Although present in undergraduate Chemistry courses, the teaching of electronegativity is little explored in the literature and treated in a fragmented way in many materials. In this way, a didactic sequence is proposed for the approach of electronegativity and the scales designed by Pauling, Mulliken, Allred, Rochow and Allen directed to the first year of undergraduate in Chemistry. For a dynamic study of electronegativity models along with historical basement, modelling-based teaching is used so that students can assess scope, limitations and be able to participate in the creation of a model.