Errors in Drawing Curved Arrows

Curved arrows starts on a pair of electrons (lone pair or bond).

The tail must start on a lone pair or a bond.

In this example the arrow starts on a lone pair.

In the following example the second arrow is drawn incorrect since it does not start on a lone pair or bond.

Curved arrows end with a new bond or lone pair.

The head of a curved arrow shows either the formation of a bond, or the formation of a lone pair.

The head of a curved arrow can never show carbon forming more than 4 bonds or hydrogen forming more than 2.

Any curved arrow drawn should describe one of the 4 patterns discussed thus far.