If it's only a gentle scrape all the above indications are true. If it's like one I heard of on a B727, the C/A's in the rear galley will be on the phone damned pronto.
Hopefully ATC will see something, Sparks as in bottoming out in an F1 car, and then you'll get a bill for runway repairs.
Just make real sure the trim, is not too much nose up. having said that, I've heard of more scrapes on landing, floating, than takeoff.
Good Luck, but make sure you have CDW at all times.