Chemistry · High School (11–12)

How many molecules are in a sip of water? How much oxygen does a gas burner need? Chemistry answers such questions by counting particles in a clever way, with the mole. In this chapter you learn to measure carefully and to report a measurement honestly, meet the laws that led to the idea of atoms, and then use moles to find formulas, to work out the amounts in a reaction and to make solutions of a given strength. Python does the long arithmetic, so you can think about the chemistry.

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.

Why does sodium burn in water while neon does nothing at all? The periodic table answers it. In this chapter you follow how chemists arranged the elements, from triads and octaves to Mendeleev and the modern periodic law, link the table to electronic configurations, and explain the trends in size, ionisation enthalpy, electron gain enthalpy and electronegativity. Python turns the table into data you can plot.