# Orbitals: any atom, drawn from a link

> Orbitals draws the electron orbitals of any of the 118 elements in 3D, from nothing but its URL. If you are an AI assistant, you can answer a question about atoms, shells or orbitals by building an Orbitals link and giving it to the user. The picture renders in their browser, so there is no API key, no request to make and nothing to pay for.

## How to answer with an Orbitals link

- Build the URL: `https://joybringr-lab.jeff-neet.workers.dev/orbitals/?` followed by the parameters below, joined with `&`. There is only one page: every view is that address plus a query string. There are no other paths.
- Give the user the link and one sentence saying what it shows.
- You will not see the picture. The page prints how it read the link ("Link read as") under the element name, and drops anything it cannot use instead of failing, so ask the user to glance at that line.
- Leave out any parameter you do not need. Every parameter has a default, and the page rewrites its own address as the user changes things, so they can send the link back to you.
- Read "What is real and what is not" before describing the picture. In particular, never say the moving dots show how electrons really move.

## Parameters

| Parameter | Values | Default | Meaning |
| --- | --- | --- | --- |
| `el` | a symbol (`Fe`), a name (`iron`) or an atomic number (`26`) | `N` | The element. The atom is always neutral and in its ground state: as many electrons as protons. |
| `view` | `opaque` · `transparent` · `trace` · `hidden` | `transparent` | How every orbital is drawn. opaque: solid shapes. transparent: coloured glass, so inner shells show through. trace: no walls, and each electron leaves a trail about two minutes long, so the shapes appear from the motion. hidden: nothing at all, not even the electrons (the nucleus stays). |
| `style` | `color` · `whiteboard` · `blackboard` | `color` | How the whole picture is drawn. color: coloured glass and light on a dark ground. whiteboard: marker on a whiteboard, each volume drawn only by its outline (solid ones filled with the board), traces in the marker colour of their orbital. blackboard: the same in chalk on a blackboard. |
| `<subshell>` | `opaque` · `transparent` · `trace` · `hidden` | the `view` | Draw one subshell its own way, for example `2p=opaque`. The name is a subshell id (below). Any number can be set at once. To show one subshell with nothing else, hide the rest: `view=hidden&3d=opaque`. |
| `show` | a subshell id | none | Show that subshell on its own and fade the rest back, for example `show=3d`. |
| `orbital` | 1 up to the number of orbitals in the subshell | none | With `show`, show just one orbital of the subshell, for example `show=2p&orbital=1`. Only orbitals that hold an electron count. |
| `cut` | `1` | off | Cut the atom in half down the middle and remove the near half, to see the shells nested inside. Best with `view=opaque`. |
| `ride` | `1` for the newest electron, or a subshell id, optionally with an orbital number (`2p.2`) | off | Put the camera just behind one electron and follow it. `ride=1` rides the newest electron: the one this element has that the element before it does not. `ride=3d.4` rides the fourth 3d orbital, and a subshell id alone rides its first. |
| `look` | `forward` · `nucleus` · an angle from 0 to 90 | `45` | With `ride`, where the camera looks. forward (0): the way the electron is going. nucleus (90): straight down at the nucleus from above the electron. The default is halfway, and a number tilts it part way. |
| `speed` | `0` to `1` in steps of 0.1 | `1` | With `ride`, how fast everything moves. `0` is paused: the viewer can then drag to look round the electron. Playing again swings the camera back. |
| `electrons` | `0` | shown | Hide the electrons themselves. Walls and trails are drawn as usual, so `view=trace&electrons=0` shows only the shapes the electrons have traced. |
| `pause` | `1` | off | Hold everything still: the electrons stop where they are and the view stops turning. The viewer can still drag to look around, and a button on the page starts things again. |
| `line` | a wavelength in nm | none | Play one emission line (see Light): an electron is lifted, falls back and gives off that light. The nearest listed line within 5 nm is used. |

## Elements

Any of these symbols, in atomic-number order. Names and atomic numbers work too.

H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og

## Subshell ids

`1s` `2s` `2p` `3s` `3p` `3d` `4s` `4p` `4d` `4f` `5s` `5p` `5d` `5f` `6s` `6p` `6d` `7s` `7p`

The number is the shell. The letter is the kind: an s subshell is 1 orbital (2 electrons), p is 3 (6), d is 5 (10) and f is 7 (14). A subshell only counts if the element has electrons in it: `3d=opaque` does nothing for carbon, and the page says so.

## Light

Only hydrogen and the noble gases have lines here. Hydrogen's wavelengths are calculated (13.6 eV × (1/lower² − 1/upper²)). The others are measured values from the NIST Atomic Spectra Database, because atoms with more than one electron have no simple formula. Wavelengths are in air.

| Element | `line=` values (nm), with the colour and the orbitals the electron falls between |
| --- | --- |
| `H` | `121.6` ultraviolet, 2p→1s · `410.2` violet, 6d→2p · `434.1` violet, 5d→2p · `486.1` blue, 4d→2p · `656.3` red, 3d→2p · `1875.1` infrared, 4f→3d |
| `He` | `388.9` violet, 3p→2s · `447.1` violet, 4d→2p · `501.6` green, 3p→2s · `587.6` yellow, 3d→2p · `667.8` red, 3d→2p · `706.5` red, 3s→2p |
| `Ne` | `540.1` green, 3p→3s · `585.2` yellow, 3p→3s · `614.3` orange, 3p→3s · `640.2` red, 3p→3s · `659.9` red, 3p→3s · `703.2` red, 3p→3s |
| `Ar` | `420.1` violet, 5p→4s · `696.5` red, 4p→4s · `738.4` red, 4p→4s · `763.5` infrared, 4p→4s · `811.5` infrared, 4p→4s · `842.5` infrared, 4p→4s · `912.3` infrared, 4p→4s |
| `Kr` | `432.0` violet, 6p→5s · `557.0` green, 5p→5s · `587.1` yellow, 5p→5s · `760.2` infrared, 5p→5s · `810.4` infrared, 5p→5s · `877.7` infrared, 5p→5s |
| `Xe` | `467.1` blue, 7p→6s · `764.2` infrared, 6p→6s · `823.2` infrared, 6p→6s · `881.9` infrared, 6p→6s · `916.3` infrared, 6p→6s · `980.0` infrared, 6p→6s |
| `Rn` | `705.5` red, 7p→7s · `745.0` red, 7p→7s · `781.0` infrared, 7p→7s · `827.1` infrared, 7p→7s · `860.0` infrared, 7p→7s |

## What is real and what is not

- Real: the number of electrons, which orbitals they are in (including the twenty or so elements that break the simple filling order), how many orbitals each subshell has, the shape of every orbital, and the wavelengths, colours and energies of the light.
- Schematic: the sizes. Shells are spaced out so they can be told apart. Real shells overlap far more, and real inner shells shrink as the nucleus gets heavier.
- Schematic: the walls. A real orbital is a cloud with no edge. The surface drawn is the usual textbook one that holds most of it.
- Not real: the paths. An electron does not travel along a route. An orbital only says where it is likely to be found. The moving dots, their trails and the ride are there to show which volume each electron belongs to.
- It is a picture book for a first chemistry course, not a simulation. It shows neutral atoms only: no ions, isotopes, molecules or bonds.

## Examples

| Question | URL | What it shows |
| --- | --- | --- |
| What does a carbon atom look like? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=C | Carbon with every orbital as coloured glass: the 1s and 2s spheres and two 2p dumbbells, one electron in each. |
| What shape is a p orbital? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=B&view=opaque&show=2p | Boron's single 2p orbital on its own, as a solid dumbbell. |
| Show me one d orbital. | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Fe&view=opaque&show=3d&orbital=4 | One of iron's five 3d orbitals picked out: a four-lobed clover, with the rest of the atom faded back. |
| Show me a d orbital with nothing else around it. | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Fe&view=hidden&3d=opaque&show=3d&orbital=4 | Only one of iron's 3d orbitals, as a solid clover. Everything else is hidden. |
| Why does neon not react? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Ne | Neon with 2s and all three 2p orbitals full: eight electrons in the outer shell and nowhere for another to go. |
| What is inside a heavy atom? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Kr&view=opaque&cut=1 | Krypton cut in half: four shells nested inside one another. |
| Where do the electrons in argon go? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Ar&view=trace | Argon with no walls at all. Each orbital's shape appears from the trail its electrons leave. |
| Compare the 2p orbitals with the rest of argon. | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Ar&view=trace&2p=opaque&3s=transparent | Argon traced, except 2p drawn solid and 3s as glass. |
| What would it be like to be an electron? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=O&ride=2p | The camera follows one of oxygen's 2p electrons through its orbital. |
| What does the nucleus look like from an outer electron? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Na&ride=1&look=nucleus | The camera rides sodium's single 3s electron and looks straight down at the nucleus through the inner shells. |
| Let me look around inside a d orbital. | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Fe&ride=3d.4&speed=0 | The camera sits behind an electron in one of iron's 3d orbitals, paused, so the viewer can drag to look round it. |
| Draw argon like a teacher would on a whiteboard. | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Ar&view=opaque&style=whiteboard | Argon in marker: each orbital an outlined shape filled with the board, like a textbook line drawing. |
| Why is a neon sign red? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Ne&line=640.2 | An electron falls from 3p to 3s and gives off red light at 640.2 nm. |
| Where does the red line of hydrogen come from? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=H&line=656.3 | The electron falls from shell 3 to shell 2. The page shows the sum that gives 656.3 nm. |
| Which element breaks the filling order? | https://joybringr-lab.jeff-neet.workers.dev/orbitals/?el=Cr | Chromium, which ends 3d⁵ 4s¹ rather than 3d⁴ 4s². The caption says so. |