Here's a breakdown of what happens in a decomposition reaction:

* One larger molecule (reactant) breaks down into two or more smaller molecules (products).

Example:

* Reactant: Water (H₂O)

* Products: Hydrogen (H₂) and Oxygen (O₂)

Chemical Equation: 2H₂O → 2H₂ + O₂

The step that shows the split of one molecule into two smaller molecules is the arrow (→) in the chemical equation. This arrow symbolizes the transformation from the reactant(s) to the product(s).

Let me know if you'd like more examples or have other questions about chemical reactions!