Every formula derived from first principles - atoms to electrochemistry - so the math is something you reconstruct, not memorize.
ATOMIC NUMBER (Z): a whole number, the proton count, defines the element. MASS NUMBER (A): a whole number, protons plus neutrons, belongs to one specific isotope and appears in isotope notation (e.g., the 14 in carbon-14). ATOMIC MASS: a decimal, the abundance-weighted average over all natural isotopes, and the value printed on the periodic table. The classic trap is calling the periodic-table decimal the mass number; it is the average atomic mass, never the count of particles in any single atom.…
Every chapter runs the same four moves - discriminator, why-box, clinical bridge, and high-yield anchor - plus MCAT-format practice passages.
The Book 7 Final Review is free, and the 5,600+ card Anki deck is just $5 (free in the set). Video lectures for every chapter are coming soon, also free.
All six subject books (General Chemistry included) - ~2,220 pages of mechanism-first review. Buy once, yours forever. Book 7 is free; the Anki deck is $5 (free in the set).