| Understandings |
|---|
| Discrete energy and discrete energy levels |
| Transitions between energy levels |
| Radioactive decay |
| Fundamental forces and their properties |
| Alpha particles, beta particles and gamma rays |
| Half-life |
| Absorption characteristics of decay particles |
| Isotopes |
| Background radiation |
$$ \text{Booklet}\\\space\\\\E = hf\\\space\lambda=\frac{hc}{E} $$
Symbol for photons.
Energy on this microscopic scale is discrete. Discrete energy means that the energy of a system cannot take on any arbitrary value.
If you expose a container of gas at low pressure to a strong electric field, light is emitted from the gas. This emitted light can be analysed by passing it through a prism or diffraction grating.
The result is a series of bands of light at different wavelengths. The set of possible wavelengths that can be emitted is called an emission spectrum.
Such data have show that no two elements have the same wavelengths in their spectrum. The wavelengths are like fingerprints: they can be used to identify the element.
Each element also has an absorption spectrum cause by a cool gas between a source of light and a spectroscope.
Light sources through a spectroscope
Light source + cold gas through a spectroscope
Light source + hot gas through a spectroscope
The emission spectrum of atomic Hydrogen, the simples element, is divided into a number of spectral series. These series are name after the scientists who discovered them.
Those spectral series are: