That's a Freccia + Freccia routing. If you buy the trip in a single transaction, Trenitalia will let you take the next (one hour later) train from Padova to Firenze if the inbound train to Padova is too late.
I wouldn't worry about 12 minutes in Padova myself, but with an expensive Freccia ticket on the line, I would want this to be a single ticketing transaction (though I assume you'll end up with two tickets or two smart codes).
Splitting the trip and taking a somewhat earlier regional train to Padova is another possibility (and would probably save a bit of money), but if that regional train is canceled, you'll be out of luck unless you can figure out a way to buy that itinerary in one transaction. [Note: Dario states below that this is incorrect; Trenitalia will allow you to take a later train if a delay on an earlier Trenitalia train caused you to miss your connection.]
If you download the Trenitalia app, it will probably keep you up to date on any schedule adjustments on the day of travel. I think it may display the platform numbers for the trains, too. That would give you an idea of which direction to head in when you step off the train in Padova. But do confirm the platform by looking for one of the departure boards or screens.