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what is the lewis structure

Lewis structures, also known as Lewis dot diagrams, Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures, are diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule. A Lewis structure can be drawn for any covalently bonded molecule, as well as coordination compounds

Explanation:

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.