Is it possible to carry out the reaction of decomposition of a simple substance into several others?

By definition, a simple substance is composed of atoms of the same kind – say, atoms of hydrogen, nitrogen, iron, etc.

Trying to decompose this substance, we can get only those atoms that are included in the composition – and these, as we found out, are atoms of the same type. Atoms of the same kind are able to separate from each other only by forming the same substance – because, no matter how they rearrange with each other, this is simply a change in the order of completely identical atoms.

Accordingly, when trying to decompose a certain simple substance, we get a substance consisting of the same atoms of the same type (hydrogen, iron, etc.). In other words, it is the same substance as the original one.

Accordingly, it is impossible to decompose a simple substance into several different ones.