# BohrAtom

> The Bohr model of an element: its symbol on the nucleus and its electrons on rings, shell_gap pixels apart.

Page: https://fframes-kit.pages.dev/docs/chemistry/bohr-atom/
Cargo feature: `chemistry` (`fframes-kit = { version = "..", features = ["chemistry"] }`)

The Bohr model of an element: its symbol on the nucleus and its electrons on rings,
`shell_gap` pixels apart. The shells come from the ground state configuration, so copper is
2, 8, 18, 1. After `delay` the electrons appear one by one over `fill` seconds, innermost
shell first. Every shell turns, the outer ones slower (`speed` radians a second on the first).
With `labels` the name and the electrons per shell sit under the atom. Gallery scene:
`BohrAtom` (sodium and chlorine).

Gallery clip of `BohrAtom`: https://fframes-kit.pages.dev/media/scenes/BohrAtom-e37da4b9.mp4

```rust
use fframes_kit::prelude::*;

fn figure<'a>(ui: &mut Ui<'a, '_, '_>) -> Svgr<'a> {
    ui.show(BohrAtom {
        element: 11,
        center: (-3.6, 0.0),
        shell_gap: 50.0,
        delay: 0.5,
        enter: Some(Create::default().into()),
        ..ui.defaults()
    })
}
```

## API

Components are plain structs. Set the fields you need and fill the rest with `..ui.defaults()`: the defaults below come from the current theme (`theme.` values are fields of `Theme`).

### BohrAtom

| Field | Type | Default | Description |
| --- | --- | --- | --- |
| `element` | `u32` | `11` | Atomic number of the element drawn (11 is sodium). |
| `center` | `(f64, f64)` | `(0.0, 0.0)` | The middle of the nucleus, in units of `ui.space`. |
| `nucleus_radius` | `f32` | `46.0` | Radius in pixels of the nucleus disc that carries the symbol. |
| `shell_gap` | `f32` | `56.0` | Distance in pixels between neighbouring shell rings, and from the nucleus to the first. |
| `electron_radius` | `f32` | `10.0` | Radius in pixels of an electron dot. |
| `delay` | `f32` | `0.0` | Seconds after the container's start before the electrons begin to appear. |
| `fill` | `f32` | `1.5` | Seconds the electrons take to appear one after another, innermost shell first. |
| `speed` | `f32` | `1.2` | Turning speed of the first shell in radians per second; outer shells turn slower. |
| `labels` | `bool` | `true` | Writes the element name and the electrons per shell under the atom; `false` for none. |
| `nucleus_color` | `Color` | `theme.colors.accent` | Colour of the nucleus disc. |
| `shell_color` | `Color` | `theme.colors.muted` | Colour of the shell rings. |
| `electron_color` | `Color` | `theme.colors.highlight` | Colour of the electron dots. |
| `text_color` | `Color` | `theme.colors.text` | Colour of the name and shell count label under the atom. |
| `stroke_width` | `f32` | `theme.stroke.thin` | Outline width in pixels of the shell rings. |
| `enter` | `Option<EnterAnim>` | `None` | How the shell rings appear; `None` shows them from the start. |
| `exit` | `Option<ExitAnim>` | `None` | How the shell rings leave at the end of the container; `None` stays. |
| `parts_enter` | `Option<FadeIn>` | `None` | Fade in of the nucleus, electrons and labels; `None` for none. |
| `parts_exit` | `Option<FadeOut>` | `None` | Fade out of the nucleus, electrons and labels before the end; `None` for none. |

Methods:

- `fn shell_radius(&self, index: usize) -> f64`: The radius in pixels of shell `index` (0 innermost).
- `fn electron_angle(&self, index: usize, slot: u32, count: u32, t: f64) -> f64`: The angle in radians of electron `slot` of the `count` on shell `index`, `t` seconds after `delay`: evenly spaced, turning at `speed / (index + 1)`.

Feature `chemistry` · [Source](https://github.com/khanhthanhdev/fframes-kit/blob/main/fframes-kit/src/kits/chemistry/bohr.rs#L29)