Atoms, bonds and reactions — how matter is built and how it rearranges.
19 articles
Le Chatelier's principle predicts how a chemical equilibrium responds to concentration, pressure, and temperature changes — partially counteracting each stress while only heat actually shifts K.
A polymer is any giant molecule built from many repeating monomer units. The same architecture makes plastics, rubber, proteins, and DNA — and structure, not the monomer, sets the properties.
Dissolving does not destroy a solute — it disperses it. Water surrounds each particle in a hydration shell, but only when forces match ('like dissolves like'), and only up to a saturation limit.
Why individual radioactive decay is fundamentally random and memoryless, yet a large population halves like clockwork — with the decay law, half-life, decay modes, and dating.
The periodic table is not an arbitrary chart. Ordered by atomic number and shaped by electron configuration, its rows and columns encode why elements repeat their chemistry.
The mole is chemistry's counting unit — like a dozen, but 6.022×10²³ strong. It bridges the grams you can weigh and the particles you cannot see.
Electrons do not orbit. They occupy standing-wave probability clouds whose shapes and capacities are fixed by three quantum numbers — and those capacities are exactly why the periodic table has the blocks and row lengths it does.
Energy pours into melting ice and the thermometer does not move. The missing joules are buying something other than speed — and following where they go explains latent heat, phase diagrams, and why ice floats.
A sealed flask settles at a fixed shade of brown and stays there forever — not because the reaction ended, but because the forward and reverse reactions now run at exactly the same rate.
Collision theory, the activation-energy barrier, and the Arrhenius exponential — how chemistry decides not whether a reaction happens but how fast, and what a catalyst can and cannot change.
Bring two hydrogen atoms together and they snap into a molecule, releasing energy. The potential-energy curve explains bond length, bond strength, and why covalent and ionic are two ends of one continuum.
Where the ideal gas law comes from: count the collisions of point particles against the walls, discover that temperature is nothing but average molecular kinetic energy, and read off PV = nRT.
pH is a logarithm, which is why one unit is a factor of ten and why your blood can survive a lifetime of acidic meals. A tour of proton transfer, water's autoionisation, strong versus weak acids, buffers and titration curves.
Split a redox reaction into two half-cells and the electrons have to detour through your device. That detour is electricity — and its voltage, its limits, and its eventual death are all predictable.
Carbon makes four strong bonds and is happy bonding to itself, so it builds chains, branches, and rings without limit. Hybridisation, catenation, functional groups, and isomerism explain how one atom gives tens of millions of compounds.
Oxidation is loss of electrons, reduction is gain, and they always happen together. That one idea — tracked with oxidation states — unifies combustion, rusting, batteries, and respiration.
Diamond spontaneously turns into graphite and yet your ring survives — the gap between those two facts is the whole story of Gibbs free energy, the referee between energy and disorder.
The bonds inside a molecule are worth hundreds of kJ/mol; the forces between molecules are worth a handful. Yet it is those humble forces — dispersion, dipole–dipole, hydrogen bonding — that decide whether a substance is a gas, a liquid or a solid, and why ice floats.
Atoms absorb and emit light only at wavelengths set by their electron energy levels, so light carries a fingerprint of composition — the basis of knowing what stars, galaxies, and unknown compounds are made of, remotely.