Facile Method for Constructing Lewis (Electron Dot) Structures

Abstract

A simple method to determine Lewis electron dot structures and formal charges without a need to sum all of the valence electrons, reorganize electron pairs, draw and pair up individual electrons, or remember a formal charge formula is described. The formal charge is determined by the group number (number of valence electrons) and the number of bonds, with the sum of formal charges then being equal to the total charge. This leads directly to a valid Lewis structure. The facility of the procedure allows the student to focus more on the chemical aspects of deciding which valid Lewis structure (or structures) is the correct or most important one.

CADMIO: Creating and Curating an Educational YouTube Channel with Chemistry Videos

“…From a pedagogical point of view, drawing Lewis structures can be challenging for students because it requires several steps: sum all valence electrons, reorganize electron pairs, draw individual and paired electrons, and evaluate the formal charge to discriminate between possible structures. 32 This video provides a clear-cut methodology for drawing Lewis structures which helps students through the different steps. Videos 2 and 4 in the top five videos correspond to the lessons on the "Brief History of the Periodic Table" (11,607 views) and "Atomic Structure through Time" (4,786 views).…”

“…Undoubtedly, the “Lewis Structures: Part I” lesson (16,451 views) is the first approach to a main feature in chemistry, chemical bonding, and in this sense, it seems natural that this video has so many views. From a pedagogical point of view, drawing Lewis structures can be challenging for students because it requires several steps: sum all valence electrons, reorganize electron pairs, draw individual and paired electrons, and evaluate the formal charge to discriminate between possible structures . This video provides a clear-cut methodology for drawing Lewis structures which helps students through the different steps.…”

Quantitative Assessment on the Effectiveness of a Formal Charge Method for Constructing Lewis (Electron Dot) Structures

“…An ability to draw a Lewis electron dot structure has since become essential for a chemist to be able to rationalize the structures and chemistry of the p-block elements; thus, it is usually taught quite early on in high school chemistry curricula. Nonetheless, methods for drawing Lewis electron dot structures have changed very little, despite many students struggling with the method − and a fairly large number of publications offering alternative or modified procedures. ,,− The vast majority of these procedures involve three key steps: calculate the total number of valence electrons, draw the skeletal structure, and distribute the remaining electrons . Generally, the formal charges might be determined after this to decide between possible structures.…”

“…We call these “traditional methods”. A few methods use an electron-pairing process of the valence electrons that avoids the calculation of a total electron count. − More recently, Curnow published a fundamentally different method which uses the formal charges (as determined by the number of bonds to each atom) to determine the structure and bond orders, with the octets being completed as a final step . This method does not require a total electron count, modification steps involving the rearrangement of electron pairs, the use of a formal charge formula (or any other formula), or keeping track of electron counts.…”

A Simple Approach for Beginners to Drawing Lewis Structures, Resonance Forms, and Isomers

“…The most recent study of constructing Lewis structures was presented by Curnow 25 . The author described a method to determine formal charges of main group elements without counting the total valence and checking the Lewis structures by formal charge formulas.…”