Answer:
The lithium atom has one electron in its outer shell, so it loses that one electron and becomes a 
 ion. The fluorine atom has 7 electrons in its outer shell so it gains that one electron and becomes a 
 ion. The electrostatic force of attraction between the two ions, because of their charges, bonds them together in an ionic bond to make 
, Lithium Fluoride.
Couldn't add a diagram, but hope it helps.