Curved arrows communicate electron flow (movement)

Curved arrows indicate electron flow. The base of the curved arrow is placed at the source of the electrons that are moving. The head of the arrow is placed at the destination of the electrons. A single barbed arrow represents one electron and a double barb represents two electrons. Electrons move from regions of relative high density to regions of low density or toward electronegative elements. It is important to use accuracy and precision when drawing curved arrows. 

It is also important to consciously use the correct type of arrow.  There are four primary types of arrows used by chemists to communicate one of the following:  completion reaction, equilibrium reaction, electron movement, resonance forms.  The three other types of arrows are shown below to build discernment between them.