Using Electronegativity to Identify Atoms Bearing Charges after Formal Charge Calculation

Textbooks provide accurate statements about the concept of formal charge, but they do not provide information about the actual charges or which atoms bear more of the actual charge. Some statements in textbooks can be misleading as they seem to hint that an atom with a formal charge carries more of the actual charge. As students progress beyond general chemistry, this misleading information or lack of knowledge can hinder their understanding of reaction mechanisms in organic chemistry courses. This work demonstrates that in common molecules, whether electrically neutral or charged, the partial negative charge is primarily on the more electronegative atom in bonded atoms and the partial positive charge is primarily on the less electronegative atom in bonded atoms, regardless of the formal charge. Including clear explanations in class about which atoms bear charges will help students better understand the concept of formal charge and their studies of reaction mechanisms in upper-level organic chemistry courses.