Chess Guide for the Intermediate Player/Some basics for openings/Answer for Exercise 2

Bxf7 WRONG Nice try, but Black can play 4. ... Kf7. You need to checkmate in 1 move!
Qxe5 WRONG The e5 pawn is defended by Black Knight on c6, so he can take your Queen now! Try again!
Qxf7 RIGHT That's right! Now we see a game that ends in 4 moves. So if you are playing a game, remember to keep f7 safe! We'll see more ways to defend it later.
Others WRONG That isn't a check! Please look for check.