The periodic table
Elements sorted by proton count. Columns share chemical behaviour because they share outer electrons.
Atoms, bonds and reactions that build every material.
Elements sorted by proton count. Columns share chemical behaviour because they share outer electrons.
Ionic bonds transfer electrons; covalent bonds share them. That single difference sets melting point, solubility and strength.
A log scale of hydrogen ion concentration. Each step is 10× — lemon juice is 100× more acidic than tomato.
PV = nRTn = m / MLiquids stack by density — mass per unit volume — because heavier fluids sink beneath lighter ones.
Heat oxidises the sugars in the juice, browning them before the paper itself burns.