Chemxus
Begin with a question.
Chemxus is organized by what you want to understand, not by a national syllabus.
If you are curious about chemistry
Start with “From alchemy to chemistry,” then “Element, atom, molecule.” These articles require no prior chemistry.
If you want to read structures
Read the two Foundations articles in order. They separate atom counts from atom connections before introducing molecular data.
If you want to work with chemical data
Begin with “What is cheminformatics?” and then “A first look at SMILES.” You do not need to program yet; the first goal is to understand what a representation preserves.