Check Mate in 1 (Chess problems)

I will be uploading chess problems for you to practice your tactics and progress in this marvelous sport. I will be uploading 5 problems every day. You can write the solution in the coments.

1st problem:

2nd problem:

3rd problem:

4th problem:
![check mate in 1.GIF]

Last problem:

If you tell me I will upload 5 chess problems every day. That is the best solution to learn and practice chess.