An element cannot be broken down into other substances by chemical or physical means. But you can still split a sample of an element into smaller pieces. For example, a piece of aluminum foil can be cut in half and then in half again, and all of the pieces will still be aluminum. What do you think will eventually happen if you could continue dividing that piece of aluminum foil You will reach the smallest possible piece of the aluminum.
You will divide the aluminum into two smaller elements.
You will continue dividing the aluminum forever into smaller and smaller pieces.
You will reach a point at which there is no matter left.