That is a difficult topic... In Italian, accents at the end of words ARE important, but many people forget to use them nonetheless... Even because of the big use of mobiles.
The accent here should be grave BUT
there are some publishers that put the í with acute accent, because phonetically it sounds like an acute accent, even if the rule says that it's grave.
Sorry if my reply was pretty confused. Please stick to the grave accent on the "i"...
Venerdì, così, sì, lì...
Perché has an "accento acuto", caffè has an "accento grave". In Italian, as general rule (not followed by everybody, but I wouldn't dig too deep into it), only the e can have the accento acuto. Other letters have always the other one. Città, papà, autorità, farà Così, lì, sì, martedì Andrò, mangiò, però Virtù, giù
If you find any vocabulary with the pronounciation it will be easy to understand the difference between the sounds, I hope. :)