Each learning path is one chapter: a guided route through a topic, one small course at a time. Pick a class to see its chapters in order.
A sodium street lamp glows yellow, and a neon sign glows red. The light comes from the atoms themselves, and each kind of atom gives its own colours. How can an atom tell us what it is like inside? In this chapter we follow the experiments that gave us the nucleus. Then we read the light of hydrogen, and we meet Bohr's model, the waves of matter and the orbitals. At the end we can write the electron configuration of any atom. Python helps us with the calculations.
In the last chapter the atom was the smallest piece of an element that we counted. But is the atom really the end of the road? In this chapter we open it up. We meet the three particles inside it, and we follow the experiments that gave us the nucleus. We learn how the electrons are arranged in shells, why this decides how an atom combines with others, and why two atoms of the same element can have different masses. Python helps us with the counting.