Not a sphere with rings drawn on it — an actual probability cloud, sampled from the real orbital math. Drag to rotate, scroll to zoom, and switch orbitals below.
An electron doesn't circle the nucleus like a planet — it exists as a smeared-out wave, a cloud of probability with a genuine 3D shape. That shape depends on the orbital: 1s is a sphere, 2p is a dumbbell, 3d branches into four lobes. The cloud above is drawn from that real math, not from an artist's guess.
99.9%Empty Space
Remove the empty space from every atom in your body and all that's left would fit in a sugar cube.
10⁻¹⁵mNucleus Diameter
The nucleus is about 100,000 times smaller than the atom it sits inside.
1926Year the Cloud Won
Schrödinger's wave equation replaced Bohr's fixed orbits with probability — the model this page renders.
TWO MODELS, SIDE BY SIDE
Bohr vs quantum
Both panels are live 3D. The left one is how the atom was taught for a century. The right one is how it actually behaves.
1913 · BOHR MODEL
Electrons on fixed circular shells at set distances (here sodium: 2 · 8 · 1). Clean, intuitive, and provably wrong about shape.
1926 · QUANTUM MODEL
Electron position as a probability cloud — denser where it's more likely to be found, never a fixed point.
HOW TO READ AN ORBITAL
Four numbers describe every electron.
Every cloud in the simulator is one solution of the Schrödinger equation, and each solution is labelled by four quantum numbers. Learn to read them and the periodic table stops being a list to memorise.
n
Principal · size & energy
n = 1, 2, 3 and up. The larger n is, the farther out the cloud sits and the more energy the electron has.
l
Angular · shape
l runs from 0 to n − 1. l = 0 is an s orbital, 1 is p, 2 is d, 3 is f.
mₗ
Magnetic · direction
Which way the orbital points. There are 2l + 1 choices: one s, three p, five d, seven f.
mₛ
Spin · up or down
Every electron has spin +½ or −½. Two electrons can share an orbital only if their spins are opposite.
RULE 1
Aufbau · lowest first
Electrons fill the lowest-energy orbitals first: 1s, 2s, 2p, 3s, 3p, 4s, 3d and on. A few elements, like chromium and copper, bend the order.
RULE 2
Pauli · two per orbital
No two electrons share all four quantum numbers. That caps each orbital at two electrons, and each shell n at 2n²: 2, 8, 18, 32.
RULE 3
Hund · spread out first
Within a subshell, electrons occupy separate orbitals with parallel spins before they pair up, like passengers taking empty bus seats.
THE LONGEST EXPERIMENT IN HUMAN HISTORY
2,400 years of asking what matter is.
It started with two Greek philosophers and one stubborn idea. It took chemists, physicists, and a few thousand experiments to turn it into the picture you can rotate at the top of this page.
0years between Democritus's “atomos” and the probability cloud on this page. Scroll down the timeline to watch the atom lose, one model at a time, every idea people were sure about.
SEVEN PICTURES OF THE ATOM
Every model was right, until it wasn't.
Each model explained what people could measure at the time, then broke on the next experiment. Pick one to see what it got right and what ended it.
What it got right
Where it broke
By the numbers
HOW SMALL IS SMALL
Eight orders of magnitude, atom to quark.
Each step down in this scale is ten times smaller than the last. From the edge of the atom to the smallest thing anyone has measured, you cross eight of them.
10⁻¹⁰ m
The atom
About ten million atoms fit across one millimetre. Nearly all of an atom's volume is the electron cloud.
10⁻¹⁴ m
The nucleus
About 100,000 times smaller. Scale the atom to a 100 m stadium and the nucleus is a grain of sand at the centre, holding over 99.9% of the mass.
10⁻¹⁵ m
Proton & neutron
Each is roughly 1.7 femtometres across, and is itself a swarm of quarks and gluons.
<10⁻¹⁸ m
Quark & electron
No experiment has found any size for them. Their radius is below 10⁻¹⁸ m, so far as anyone can tell they are points.
Masses are in MeV/c². A free neutron is unstable: it decays in about 15 minutes. Inside a nucleus it can be stable.
THE PEOPLE BEHIND THE ATOM
Eighteen minds, one model.
No single person discovered the atom. It was assembled by philosophers, chemists, experimentalists and theorists — some of whom disagreed with each other for the rest of their lives.
IN THEIR OWN WORDS
What they said about it.
Amazement, disbelief, and a little unease. Even the people who built quantum mechanics kept arguing about what it means.
Quotes marked “widely attributed” are commonly credited to the speaker but their exact source is uncertain.
ALL 118 ELEMENTS
Every element, by name.
Hydrogen to oganesson. Select any element, then open it in the simulator to see its real orbital cloud. Thirteen of them are named after scientists from the section above.
Quantum Atom 2.0 is a pair of browser tools: one shows you the electron cloud, the other takes you inside the nucleus. They share the same element, so you can move between them without losing your place.
TOOL 01 · ATOM SIMULATOR
See the electrons
Every element and 52 molecules, drawn as true orbital-shaped probability clouds.
118 elements and 52 molecules, searchable, with a data tab for each
Real Image Mode with colour types: Ember, Brand, Warm, Red, Classic, Radial, Angular and Shell
Excited state shows an electron jumping between orbitals
4D mode draws the atom in spacetime: time runs along an axis through the nucleus, as five snapshots or one continuous worldtube, with speed and reverse controls
Antimatter flips the whole scene to its mirror colours
Smooth, Ultra, Surface and Volumetric render modes, plus a Cartesian grid
Controls for cloud density, jitter and zoom, so it runs on a phone or a workstation
Shareable links to any element, e.g. #el=Fe
Zoom into the core and the very same live nucleus as in the Nucleus Explorer appears right inside the simulator, quarks and gluons included. Keep going, down to the Planck length
Zoom past the electrons into the protons and neutrons, and past those into the quarks.
Every element's proton and neutron count, built as a real 3D cluster
Scroll to zoom from the whole nucleus down to individual nucleons, then to up and down quarks
Tap a nucleon to focus on it and read its structure
Holo, Volumetric and Antimatter modes, with the same controls as the Atom Simulator
Keep scrolling in: past the quarks, through eighteen more orders of magnitude, to the Planck length (1.6 × 10⁻³⁵ m), where virtual particle pairs flicker and spacetime foam churns
A live scale ruler shows exactly how small your view is, and Dive to Planck flies you there in one click. Switch the vacuum between a flat 2D view and a 3D fly-through you can drag to look around
← →step through elements/search+ −zoom (Nucleus)0fit (Nucleus)Escclear focusdragrotate
WEBGLTHREE.JSFREENO INSTALLPHONE & DESKTOP
CHANGELOG
Built for 2.0
The physics hasn't changed — the atom still obeys the Schrödinger equation. What changed is how deep you can look and how honest the shapes are.
RENDERING
True Orbital Geometry
Every cloud on this page is sampled from real orbital probability distributions — the same shapes that show up in a chemistry textbook, rendered as points in space.
INTERACTION
3D Everywhere, For Real
Hero, comparison, and cards all run in genuine WebGL space you can drag and rotate — nothing here is a flat image pretending to be 3D.
DEPTH
Deeper Nucleus Explorer
Zoom past the nucleus into individual nucleons, and past those into the quark structure that makes them up.
QUESTIONS
Good questions, short answers.
Why a cloud instead of orbits?
Quantum mechanics describes an electron with a wave function. Squaring it gives the probability of finding the electron at each point, so the cloud is denser where the electron is more likely to be. There is no path to draw, only odds.
Is this what an atom really looks like?
No picture is literal, because atoms are far smaller than the wavelength of visible light. The clouds are computed from the orbital mathematics, the same shapes chemistry textbooks show, and drawn as points of light so you can see their form.
What does Real Image Mode do?
It switches to a photographic-style rendering and lets you choose how the cloud is coloured: Ember, Brand, Warm, Red, Classic, Radial, Angular or Shell.
What does Antimatter mode show?
It swaps the scene to a mirror palette. In the Nucleus Explorer, protons and neutrons are relabelled as antiprotons and antineutrons.
Are the electron configurations correct?
They are ground-state configurations using the Madelung filling order, with the known exceptions (chromium, copper, palladium, gold and several lanthanides and actinides) applied. For the heaviest elements they are predictions, since those atoms exist for only fractions of a second.
Does it run on a phone?
Yes. On small screens the panels become a bottom sheet, and the cloud density is lowered by default so it stays smooth. You can raise it in the Cloud & Zoom controls.
Can I share a link to one element?
Yes. Add the symbol to the address: simulation.html#el=Fe opens the simulator on iron, and the Nucleus Explorer accepts the same form.
Is it free?
Yes. It runs in the browser with nothing to install.
Stop reading about atoms. Rotate one.
Free, browser-based, no install. Every element, every orbital, rendered live.