Florida-Spectrum Environmental Services
Florida Spectrum: Chemical Fact Sheet: Iron
A very good summary of basic information about iron, including its uses, physical and chemical properties, and role in the earth.
Florida-Spectrum Environmental Services
Florida Spectrum: Chemical Fact Sheet: Krypton
A good summary of the basic data and uses of krypton.
Other
Web ref.org: Iron
A well written, easily followed entry on iron, its properties and compounds, as well as uses. Student friendly.
University of Kentucky
Chem Comics: Krypton
All sorts of comics (especially Superman) where krypton comes into play. Nice graphics for a presentation or report.