So long as your board isn't a dinosaur, it should utilize all 16GB regardless. The question would be whether it could take advantage of the 2400 MHz speed or will run it at a lower one. If you look up the specs for the motherboard, under memory it should say something like this:
So you'd just want to see if 2400 is listed there and whether it would need overclocking (O.C., of course). If it's supported by default, then you're golden.
EDIT EDIT: If it's not, then technically you should still be able to use it (you'll still get your 16GB, just running at a slower, supported speed than 2400MHz), but if you have no interest in overclocking then there's some potential there to cut down a little on cost if you look for the same type/amount of memory, just at a slower speed that the board supports.
EDIT: But while you're there you might as well double-check the maximum memory supported just to be sure. They're usually in the same spot.
I don't foresee that being a problem, though.