Matter & Reactions
Start with what holds two atoms together, then follow reactions through speed, balance, and the transfer of protons and electrons.
18 articles
- 1Chemistry11 min
Atomic Structure and the Periodic Table
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.
- 2Chemistry10 min
Radioactivity: Random Decay, Predictable Half-Life
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.
- 3Chemistry10 min
The Periodic Table: Why the Pattern Repeats
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.
- 4Chemistry10 min
The Mole: Chemistry's Bridge to the Invisible
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.
- 5Chemistry10 min
Spectroscopy: Reading Matter with Light
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.
- 6Chemistry10 min
Why Atoms Bond
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.
- 7Chemistry10 min
Intermolecular Forces and Why Water Is Weird
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.
- 8Chemistry10 min
Polymers: The Chemistry of Long Chains
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.
- 9Chemistry10 min
Solutions: Where Does the Sugar Go?
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.
- 10Chemistry10 min
The Ideal Gas Law and Kinetic Theory
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.
- 11Chemistry10 min
Phase Transitions
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.
- 12Chemistry10 min
Reaction Rates and Catalysis
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.
- 13Chemistry10 min
Free Energy: Why Reactions Happen
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.
- 14Chemistry10 min
Chemical Equilibrium
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.
- 15Chemistry10 min
Le Chatelier's Principle: How Equilibrium Pushes Back
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.
- 16Chemistry10 min
Acids, Bases and pH
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.
- 17Chemistry10 min
Redox: The Chemistry of Electron Transfer
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.
- 18Chemistry10 min
Electrochemistry: How Batteries Work
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.