The Table
One hundred and eighteen wooden blocks. Each one carries a letter carved into the grain. Tap any block to see what's inside it — and combine two of them to make something new.
How to use this table
Tap any block to see its electron shells, valence slots, and the real scientific data on the side panel. Tap the slots in the compound mixer below to load elements into your mix. Adjust quantities and combine — the mixer will tell you whether you made something real, made something close, or made nothing at all.
Compound Mixer
The valence slot rule
Every block on the table has open slots where it wants to bond — that's the orbital cloud you see when you flip a block over. Hydrogen has one open slot. Oxygen has two. Carbon has four. To combine atoms into a stable compound, you have to fill all the slots on both sides. That's why water is H₂O: oxygen has two slots, hydrogen has one slot each, so you need two hydrogens per oxygen. The math isn't arbitrary. It's the geometry of the atom.
The Atom
In 1913, Niels Bohr drew electrons as planets orbiting a sun. He was wrong, but it was the best wrong anyone had. The real atom is a fuzzy probability cloud — electrons don't have positions, they have likelihoods. Here's what that actually looks like.
What you're watching
Each dot is one possible position for an electron at one moment in time. The cloud is the sum of all those positions — denser where the electron is likely to be, thinner where it's unlikely. The nucleus at the center holds the protons and neutrons. Drag the energy slider to see what happens when electrons jump between shells. That jump — and the photon it releases — is why fire is orange and the sky is blue and your phone screen lights up at all.
The shape is the element
The outer electrons of an atom don't trace neat circles — they occupy orbitals, three-dimensional regions shaped by the math of the Schrödinger equation. s-orbitals are spheres. p-orbitals are dumbbells — two lobes, like a flattened figure-eight. d-orbitals are four-leaf clovers. f-orbitals are even more complex multi-lobed roses. Which shape an element shows depends on where it sits on the table. Hydrogen and helium: spheres. Carbon, oxygen, the whole p-block: dumbbells. Iron, copper, gold and the transition metals: clovers. This is the thing the flat ring diagram in your 1985 textbook could never show you.
↯ The orbital that breaks the rule
You just learned "d-orbitals are four-leaf clovers." Four of the five are. The fifth — dz² — is a dumbbell wearing a donut: two fat lobes on the vertical axis with a ring around its waist. Select a transition metal above and hit ↯ Show dz² to watch the clover become the rule-breaker. The lesson isn't "you were wrong." It's that "all d-orbitals are clovers" was a box, and the box had an exception living inside it the whole time. Most rules do. The job is to find the dz².
Why the lightning
When an electron jumps between energy shells, it absorbs or releases a photon. In a chunk of metal — say, the filament in an old light bulb — billions of those jumps happen per second. The visible result is light. The invisible result is heat. Same physics. Same dance. The atom is electric, and it never stops.
The void you can see now
Spin a dumbbell (any p-block element) and look at the dashed grey ring through the middle. That's the nodal plane — a flat sheet of space where the electron's probability is exactly zero. The electron is in the top lobe, or the bottom lobe, but it is never, ever in the plane between them. It doesn't slow down crossing it. It's simply never there. A radial node does the same thing in rings: pick Aluminum or Gold and you'll see gaps inside the cloud — shells of nothing the electron skips over. The empty parts of the atom are as real as the full ones.
What this model fakes (and what it doesn't)
Honesty, the way Lester's Method asks for it. Real: the lobe shapes come from the actual angular probability math (cos²θ for p, the rose curves for d and f, (3cos²θ−1)² for dz²), and the nodal plane and radial gaps are genuine — they're where the wavefunction crosses zero. Faked: this shows only the outer orbital, not the full stack (carbon is really 1s²2s²2p², we draw the 2p); the clover is flattened into a plane for legibility; and the colors are chosen by us, not by nature — electrons don't glow gold. It's a true map drawn at low resolution. If you want the high-resolution version, the handoff is below.
↳ Want to dig in deeper
This lab teaches you to recognize the shape. If you want to fly through a million-particle cloud rendered from the raw wavefunction — slice it open, isolate one orbital, see the real fog — that's a different tool, and a good one:
→ Lisyarus WebGL Orbitals — fast, minimal, hydrogen 1s through 4f, cloud + surface modes.
→ The Orbitron (Univ. of Sheffield) — the academic reference: wave functions, dot-density plots, radial distributions, every orbital named.
Recognize the shape here. Go see the math there. That's the order.
The Nucleus
Strip away the electron cloud and what's left is the nucleus — a tightly packed bundle of protons and neutrons holding 99.9% of the atom's mass in 1/100,000th of its volume. Zoom deeper and the protons themselves break open. Down there: quarks. Three of them per proton, glued together by the strong force.
Scale check
If an atom were the size of a football stadium, the nucleus would be a marble at the 50-yard line. Everything else is empty space full of electron probability. You are 99.999999999999% empty space. The reason you don't fall through your chair is electromagnetic repulsion between the electron clouds of your atoms and the electron clouds of the chair's atoms. Solidity is an illusion. Repulsion is the truth.
What you're looking at as you zoom
At low zoom: the whole nucleus, a tight ball of protons (red) and neutrons (blue). Push the zoom up and a single proton fills the screen — and inside it, three quarks. Two "up" quarks and one "down" quark for a proton. Two "down" quarks and one "up" quark for a neutron. The quarks are held together by gluons exchanging color charge. The strong nuclear force is the strongest force we know about. It has to be — the protons in the nucleus are all positively charged and would otherwise blow each other apart. The strong force is what holds matter together.
The Higgs field is here too
Every quark you see in there has mass. Every proton has 1 GeV worth of energy locked up as mass via E=mc². But quarks don't have mass on their own — they get it from interacting with the Higgs field, which fills all of space. The Higgs boson, confirmed at CERN in 2012, is the particle excitation of that field. Without the Higgs field, all matter would be massless and the universe would have no atoms, no stars, no chairs, no chemistry. Yuki's grandmother was alive because of the Higgs field. The bomb that fell on her city worked because of the Higgs field. Same field. Same equation. Different choices.
The Splitter
Florida State University, 1960. A six-year-old kid in Tallahassee sees big pipes through a fence. Decades later, those pipes are still running. From the tandem Van de Graaff in the pine flats to the 27-kilometer ring under the Franco-Swiss border, the question is the same: what happens when you hit an atom hard enough to break it open?
How an accelerator actually works (the Fox Lab method)
A negative beam of charged particles enters the tandem Van de Graaff at the low-energy end. Two rotating chains build up enormous static charge — the same physics as rubbing a balloon on your hair, scaled up by a factor of ten million. That charge creates a voltage potential that yanks the negative beam toward the high-energy end. At the midpoint, the beam hits a thin foil called a stripper foil. The foil strips away the beam's electrons. Now positively charged, the beam is repelled by the same potential — and accelerated again, in the same direction. Then it's injected into the superconducting linear accelerator, which more than doubles the energy. That's how you split an atom: first you strip its electrons, then you ride the voltage.
The Higgs Boson · July 4, 2012
For 48 years after Peter Higgs predicted it in 1964, the boson was the last missing piece of the Standard Model. CERN built the Large Hadron Collider — a 27-kilometer ring of superconducting magnets buried 100 meters underground — specifically to find it. If you push this lab's energy slider to the top, you're operating at LHC scale: 13 trillion electron volts. At that energy, when two protons hit head-on, the collision briefly creates a particle that lasts for a billionth of a billionth of a second before decaying. That's the Higgs. Confirming it took thousands of physicists, billions of euros, and the largest single experimental apparatus humans have ever built. You can see why Yuki teaches this as a story about choices. The same physics that found the Higgs found Hiroshima. The accelerator doesn't care which one you build.
Cross-reference · Section 4.27
The rotating chains on the Van de Graaff generator are the same physics as the V2T wind turbines at Mount Hood — mechanical motion converted to charge differential, charge differential converted to acceleration. The Wire Lab teaches it at residential and grid scale. The Block Lab teaches it at atomic and subatomic scale. Same equation. Six orders of magnitude apart.
The History
Every model on this timeline was the best model anyone had. Every model on this timeline was wrong. The story of atomic theory is the story of being wrong in better and better ways — and learning to stay humble even when the equation finally seems to work.