That particular contraction is only used with pronouns but not nouns. So you would say I will = I'll you will= you'll we will = we'll s/he will = s/he'll they will = they'll
However, you may hear an English speaker say what sounds like "city'll" though the contraction does not actually exist in written English. I hope that helps!
I answered "The city is going to change in ten years". Isn't this a valid answer? thanks in advance