ELI5: Explain Like I'm 5

SHELL model

The shell model is like a game of musical chairs, but with tiny particles instead of people. Imagine a room with lots of chairs and lots of little balls bouncing around inside. Some of these balls are special because they are electrons, which are very important in making things happen in the world.

Now, just like in musical chairs, some of the balls will find a chair to sit on, while others will keep bouncing around. But in the shell model, we notice that some of the chairs are more special than others. These special chairs are called energy levels, and they can only hold a certain number of balls at a time.

For example, the lowest energy level can only hold 2 balls, so only 2 electrons can fit there. The next energy level can hold 8 balls, so up to 8 electrons can fit there. And so on, with higher energy levels holding more and more balls.

This is important because the electrons in an atom are arranged in these energy levels and it affects how they interact with other atoms. Just like how you might have trouble fitting all your friends on a small bench, atoms with many electrons have trouble fitting them all in the lower energy levels. This can make the atom act differently than one with fewer electrons.

So, the shell model helps us understand how electrons are arranged in atoms, which affects how atoms interact with each other.