Steric effects

Steric effects are like when you try to put a square block into a round hole - it just doesn't fit! Just like how your toys won't fit into certain spaces, molecules also have a shape that can affect how they react with other molecules.

Molecules are made up of atoms, which are like tiny building blocks, and they can connect to each other to form a variety of shapes. Some shapes have open spaces and some shapes are really cramped with no room to move around. When molecules come into contact with each other, their shapes can either allow them to fit together like puzzle pieces or prevent them from connecting due to their shapes not matching.

Think of your toy blocks again - the square one won't fit into the round hole because of its shape. This is like steric hindrance, which occurs when molecules have shapes that prevent them from connecting and reacting. Maybe you've also played with building blocks that are a certain size and shape - if you try to stack them on top of each other in the wrong order, they become really unstable and might fall down. It's similar with molecules - if they don't fit together in the right way, they might not be able to react and form new compounds.

Overall, steric effects have to do with the shapes of molecules and how they interact with each other. Sometimes those shapes can prevent reactions from happening, just like how your toys might not fit together in certain ways.