Science lessons
Mini lessons centered on one idea, one example and one trap to avoid.
Why the periodic table worksAtomic number defines the elementElectron shells and periodsValence electronsUnderstanding ionization energyElectronegativity without shortcutsAtomic radius is not a hard sphereIonic radius: why charge mattersIsoelectronic seriesOrbitals: beyond the planetary modelPauli and Hund: two different rulesWhy Cr and Cu are famous exceptionsIonic bonding beyond electron transferCovalent bonding: sharing is a modelWhy molecular shape changes propertiesThe mole: counting without countingStoichiometry: reading equations as ratiosLimiting reactant: what runs out first?Ideal gas: a model, not a perfect real gasTemperature: what a thermometer really measuresEnthalpy: why ΔH is not simply heatEntropy without the word disorderGibbs free energy and spontaneityActivation energy: favorable does not mean fastAcids and bases: several useful definitionspH: a logarithmic scaleRedox: follow the electronsHalf-life: a statistical propertyPhoton: linking energy, frequency and wavelengthSpectroscopy: reading an energy signatureSuccessive ionization energiesElectron affinity: mind the signEffective nuclear chargePeriodic trends: understanding the exceptionsFormal charge: an accounting toolResonance: one molecule, several drawingsIntermolecular forcesHeat capacity and specific heatWave-particle dualityRadioactive decay lawIsotopes and average atomic massThe mole and Avogadro constantOxidation statesBalancing a redox reactionpH: understanding the logarithmic scaleIdeal gases: linking pressure, volume and temperatureGibbs free energy and spontaneityElectron configuration: reading atomic architectureIonic or covalent? Think continuumLewis structures: what the drawing really saysVSEPR: predicting molecular geometryMolecular polarity: dipoles add as vectorsSolubility: why some substances mixEquilibrium constant: reading K without a false storyLe Chatelier's principle: reasoning beyond a recipeReaction rate: collisions, mechanism and concentrationQuantum numbers: labeling electronic statesNuclear binding energy and mass defect