“Kill” isn’t usually the term used in chess, but pieces get “killed” in that they get captured or taken, which removes them from the board.
The king is never captured in chess; it’s put in check or checkmate. Checkmating the king wins the game, so this is probably what is meant by “killing” the king.
So, yes, the queen can “kill” the king by placing it in checkmate. This means the queen is attacking the enemy king and the attack can’t be blocked, or the king can’t move out of the line of attack.
All of the pieces on the board can check or checkmate a king except for the other king. Kings must always have at least 1 square between them.
The Queen can “kill” the King in chess by checkmating it.
