Only half of each board is shown in the answers
Diagram 3:  Checkmate. The black king is in check from the white rook. It is still in check from the rook if it moves to d8 or f8. It cannot move to d7,e7 or f7 since it would be in check from the white king.
Diagram 6: Stalemate . The black king is not in check but cannot move without moving into check from the white queen.
            
 Diagram 3                                                                               Diagram 4

     Diagram 5: Neither. The black king is not in check but cannot move without going into check. However, the black pawn can move so this is not stalemate.
It is only stalemate if a player has no moves he can make.
Diagram 6: Stalemate. The white king cannot move to g2 without being in check from the bishop on h3 . It cannot move to g1 as it would be in check from the pawn. It cannot capture the black pawn as it would be in check from the bishop on g3
 Diagram 5                                                                                                                 Diagram 6

If you are following the pages in order you have only 2 more rules to learn. You could leave these until a little later because you know enough to start playing.

If you want to learn the two rules now click "Castelling " on the black bar below.

I would recommend that you look first at "Checkmating with the queen 1"

Remember that you can also click to go to the index or any topic.