1. Sunbeds and stars... Ionization, excitation and line spectra

2. e Hydrogen Atom Electron absorbs energy and… p Incident radiation

3. p Ionisation! e Is able to completely escape from the atom

4. Ionisation! p e Energy = 0 Energy = -13.6eV Photons with a minimum energy of 13.6eV are needed to ionise a hydrogen atom from it’s ground state.

5. p e Lower frequency radiation Hydrogen Atom Electron absorbs radiation and…

6. p Is only able to move to a higher energy state within the atom Excitation! e

7. p 10eV e -3.6eV -13.6eV The electron in its excited state is unstable and so it drops back, releasing the energy as a photon. One photon with a specific amount of energy is released in an electron transition

8. Ionisation and excitation in a fluorescent tube High Voltage Argon Mercury e e e e + - High voltage - electrons bombard mercury atoms Excitation occurs - unstable electrons fall backExcitation Ionisation allows the current to flowIonisation

9. Fluorescence High voltage + - Argone e e e Phosphorous coating e e

10. Ground state -13.6eV Ionisation 0eV Electron transitions Spectral transitions in hydrogen

11. Spectroscopy Wavelength of radiation emitted or absorbed Intensity Looking at the signatures of elements