The only stupid question is the one you don't ask 
, questions are how we learn! In this case you will need to further define breadboard. If you mean the one that appears by default in breadboard view, then no an 805 SMD led won't connect to it (as it has no pins only 2 flat areas meant to be soldered to a board). If you want to use a real breadboard you will be better off with something like a standard t3 or t5 led that has wire leads that will plug in to a breadboard. The 805 leds are reputed (although I haven't actually done it) to be able to be soldered (with difficulty!) on the pads of perfboard if you really want to experiment with SMD devices. They can also be soldered (with difficulty!) to an adapter PCB designed to convert smd parts to .1 pins suitable for a breadboard. We would probably need to know more about what you are trying to do to provide better advise.
Peter Van Epp