Answer
Left arrow: Going from a bond to a lone pair.
Right arrow: Going grom a lone pair to a bond.
Work Step by Step
1. Identify where the tail of the arrow is:
Left arrow: The tail is clearly on a bond.
Right arrow: The tail is clearly on a lone pair.
2. Identify where the head is going to:
Left arrow: It is going to an oxygen atom. (It is going to form a lone pair)
Right arrow: It is going to a carbon atom. (It is going to form a bond)
** Most of the times, the head going to a carbon is going to be a bond, and other atoms, just a lone pair.
Therefore:
Left arrow: Going from a bond to a lone pair.
Right arrow: Going grom a lone pair to a bond.
