The Chemistry of Art > The Structure of the Atom and Colours >
By the twentieth century, chemists were using a range of technologies to study the spectra, leading to increased understanding about the origins of colours of different elements
Students learn to:
- identify Na+, K+, Ca2+, Ba2+, Sr2+, and Cu2+ by their flame colour
- explain the flame colour in terms of electrons releasing energy as they move to a lower energy level
- explain why excited atoms only emit certain frequencies of radiation
- distinguish between the terms spectral line, emission spectrum, absorption spectrum and reflectance spectrum
- describe the development of the Bohr model of the atom from the hydrogen spectra and relate energy levels to electron shells
- explain what is meant by n, the principal quantum number
- identify that, as electrons return to lower energy levels, they emit quanta of energy which humans may detect as a specific colour
- outline the use of infra-red and ultra-violet light in the analysis and identification of pigments and their chemical composition
- explain the relationship between absorption and reflectance spectra and the effect of infra-red and ultra-violet light on pigments including zinc oxide and those containing copper
Students:
- perform first-hand investigations to observe the flame colour of Na+, K+, Ca2+, Ba2+, Sr2+, and Cu2+
- gather and process information from secondary sources to analyse the emission spectra of sodium and present information by drawing energy level diagrams to represent these spectral lines
- gather, process and present information about a current analytical technology to:
- describe the methodology involved
- assess the importance of the technology in assisting identification of elements in samples and in compounds, and
- provide examples of the technology’s use
- solve problems and use available evidence to discuss the merits and limitations of the Bohr model of the atom
Extract from Chemistry Stage 6 Syllabus (Amended October 2002). © 2009, Board of Studies NSW