Question about elemental dmg and monsters

i've just made myself some bows with differrent elemental dmg. icy, fiery, shocking, earth etc. What i want to ask is, does anyone know which monsters are weak against earth or lightning dmg? while some monsters are obvious as to which element they r weak against, (eg ice imps weak against fire) other monsters give no clues as to which elemental dmg they are weak against. It's also rather tiring to have to switch bows to see which deals the most dmg. I would appreciate it if someone could tell me how to recognize elemental weakness. Or even better if anyone has a link to a complete table of such stats. thank you very much

In the desert the big rock monsters that are similar to stone elementals are weak against Air, and I think some types of Gargoyles are weak against Earth, but thats all I can think of.

hmm what about lightning?