The molecule that can split into oxygen and hydrogen atoms is water (H₂O).

Here's why:

* Composition: Water is made up of two hydrogen atoms bonded to one oxygen atom.

* Electrolysis: When an electric current is passed through water (a process called electrolysis), the bonds between the hydrogen and oxygen atoms break.

* Products: This process releases hydrogen gas (H₂) and oxygen gas (O₂).

The chemical equation for the electrolysis of water is:

2H₂O → 2H₂ + O₂