ChemicalElements.com: Tantalum
Basic information, atomic structure, and isotopes.
EnvironmentalChemistry.com: Tantalum
Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Tantalum
Basic physical and historical information.
Lenntech: Tantalum
Physical data, chemical properties, health and environmental effects.
Visual Elements: Tantalum
Discovery, uses, physical information, and key isotopes.
WebElements: Tantalum
Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Tantalum
Properties of the element, including its history, applications, and characteristics.