Nitrogen

LANL: Nitrogen - History, sources, natural compounds, and ammonia.
http://periodic.lanl.gov/elements/7.html

EnvironmentalChemistry.com: Nitrogen - Atomic structure, chemical and physical properties, and table of nuclides.
http://environmentalchemistry.com/yogi/periodic/N.html

ChemGlobe: Nitrogen - Electronic, thermal, and steric data along with basic facts and an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/7.html

It's Elemental: Nitrogen - Basic physical and historical information.
http://education.jlab.org/itselemental/ele007.html

USGS Minerals Information: Nitrogen - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
http://minerals.usgs.gov/minerals/pubs/commodity/nitrogen/

Visual Elements: Nitrogen - Animation, uses, physical information, and key isotopes.
http://www.chemsoc.org/viselements/pages/nitrogen.html

Especiál Gas Inc.: Nitrogen - Numeric data, uses, and general information.
http://www.c-f-c.com/specgas_products/nitrogen.htm

ChemicalElements.com: Nitrogen - Basic information, atomic structure, and table of isotopes.
http://www.chemicalelements.com/elements/n.html

WebElements: Nitrogen - Extensive information on history, uses, occurrence, compounds, and properties of the element.
http://www.webelements.com/webelements/elements/text/N/key.html

Wikipedia: Nitrogen - Properties of the element, including its history, applications, and characteristics.
http://en.wikipedia.org/wiki/Nitrogen

Lenntech: Nitrogen - Physical data, chemical properties, health and environmental effects.
http://www.lenntech.com/Periodic-chart-elements/N-en.htm