Editing Lewis structure (section)

===Lever method===
Another simple and general procedure to write Lewis structures and resonance forms has been proposed.<ref>{{citation |author=Lever, A. B. P. |year=1972 |title=Lewis Structures and the Octet Rule |journal=[[J. Chem. Educ.]] |volume=49 |issue=12 |page=819 |doi=10.1021/ed049p819|bibcode=1972JChEd..49..819L }}</ref>{{example needed|date=March 2025}}

This system works in nearly all cases, however there are 3 instances where it will not work{{citation needed|date=October 2024}}. These exceptions are outlined in the table below.
{| class="wikitable"
|+ Exceptions
|-
! The Exception !! How it Breaks the System !! How to Fix the Lewis Structure
|-
| Free Radicals (molecules with unpaired valence electrons) || Sum of TVe will be an odd number. Bond number will not be a whole number.|| Round calculated bond number down to the nearest whole number. (e.g. 4.5 bonds would round down to 4 bonds)
|-
| Valence Shell Deficiency || Does not break the system, must instead memorize when it occurs.|| BeX<sub>2</sub>, BX<sub>3</sub>, and AlX<sub>3</sub>. "X" represents Hydrogen or Halogens. When Be is bonded with 2 other atoms, or when B and Al are bonded with 3 other atoms, they do not form full valence shells. Assume single bonds and use the actual bond number to calculate lone pairs.
|-
| Expanded Octet (only occurs for elements in Groups 3-8)|| Bond calculation will provide too few bonds for the number of atoms in the molecule.|| Assume single bonds, use the minimum number of bonds necessary to create the molecule.
|}