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  Curved Arrows: Move electrons, not atoms Curved arrows show how electrons move. Naturally, if electron movement occurs during a chemical reaction, atoms must move too. For example, atoms move closer when they form a new bond, and they move apart when a bond breaks, but curved arrows do not show these movements. Arrows are only used to show electron movements. The following drawings show wrong and right ways to draw an arrow for a bond-making reaction. The WRONG drawing uses an arrow to show (H) atom movement, while the RIGHT drawing uses an arrow to shows electron movement.
The next pair of drawings show a bond-breaking reaction. Here too, the WRONG drawing uses an arrow to show atom movement. (The arrow looks like it starts at an electron pair, but it can't show electron movement because no change would occur.) The RIGHT drawing uses an arrow to show the CBr bond pair changing into a Br lone pair.
Review problems Take some time to practice what you have learned on this page. One or more arrows are misdrawn in each reaction below. Re-draw the reactants with correct arrows. Drawing suggestion: Draw complete formulas before checking your answers. Do not simply identify misdrawn arrows and do not these problems only in your head (even if you can). #1.
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