Resumen de A Convenient Approach for the Construction of Lewis Structures by Focusing on the Valence Requirements of Outer Atoms
A convenient approach to obtain Lewis structures for compounds of the type YXn involves first constructing a trial structure that satisfies the valence of the outer atoms (e.g., 1 bond for fluorine, 2 bonds for oxygen, and 3 bonds for nitrogen) and placing the molecular charge (if any) on the central atom. The second step involves evaluating the electron count of the central atom, which can give rise to three possibilities: (i) if the central atom has an octet configuration, no change in the number of bonds is required; (ii) if the central atom (Y) exceeds the octet, a Y–X bond is relocated as a lone pair on X, which results in a formal positive charge on Y and a formal negative charge on X; and (iii) if the electron count on the central Y atom is less than an octet, a lone pair on the outer atom is relocated as a Y–X bond, which results in a formal negative charge on Y and a formal positive charge on X; these transformations modify the electron configuration around X such that it will adopt a correct Lewis structure. This approach differs considerably from other methods that require one to calculate the total number of valence electrons in the first step. As such, the method described here, which focuses on using valence as a guiding chemical principle, is much less mathematically oriented and, therefore, less subject to errors from incorrect calculations.
