Line Spectrum stacks the visible line spectra of elements on one wavelength scale in nanometers, so a line at the same wavelength sits at the same place in every strip. Each element shows a few of its strongest visible lines (three to eight) from the NIST Atomic Spectra Database, not every line it has, so the spectra stay easy to read and compare. Type your own lines instead for a made-up Element X, or edit an element’s lines to trim them.
For an “identify the unknown” question, add a mixture strip: it shows every line of the strips you tick, labeled Unknown or whatever you call it, and the answer key names what it is made of. Draw the spectra as colored lines on black, as dark lines across a rainbow, or as black lines on white for a black-and-white copier, and leave the element names blank for students to fill in.
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An atom’s electrons can only have certain energies. When an electron falls from a higher energy level to a lower one, the atom gives off light of exactly the energy difference, which is one exact wavelength. Each element has its own energy levels, so its lines are a fingerprint.
A mixture’s spectrum has every line of every element in it. Match each line of the unknown to a reference spectrum: an element is present if all of its lines appear in the unknown. The generator’s mixture strip is made exactly this way, from the strips you tick.
An emission (bright-line) spectrum is light given off by a hot gas: colored lines on black. An absorption spectrum is what’s left when white light passes through a cool gas: a rainbow with dark lines missing. An element’s dark absorption lines are at the same wavelengths as its bright emission lines.
Real spectra have many lines, some very faint (iron has thousands), which makes worksheets hard to read. Each element here has its strongest few visible lines, the ones textbooks usually show. If you want different lines, edit the element’s lines or type your own.
The NIST Atomic Spectra Database, for neutral atoms, as wavelengths in air rounded to 0.1 nm. Some lines of helium, potassium, strontium, neon and argon are past 700 nm, so widen the range to see them.
Chemistry Figures Line Spectrum