Have you ever wondered how chemists unravel the mysterious world of atoms and molecules? After all, you can't see atoms and molecules with the naked eye. So in chemistry we use models. These are algorithms that allow us to understand and predict the behaviour of atoms and molecules. A good model can separate cause from effect and explain, for example, why one chemical reaction goes faster than another. Unfortunately, we lack good models in surface chemistry. This prevents us from really understanding the chemical processes that take place on the surface of a solid. In my research group, we are developing advanced quantum chemical models that allow us to separate cause and effect in surface chemistry. We do this by bridging the gap between the electronic structure of surfaces and molecules on the one hand, and the physical properties of chemical phenomena such as chemical bonding and chemical reactivity on the other. We then use these newly developed models to unravel the mysteries of surface chemistry. This in turn opens the door to fundamentally new insights into the world of surface chemistry.