Overview and basic data.

Basic information, atomic structure, and table of isotopes.

Atomic structure, properties, and table of nuclides.

Numeric data, uses, and general information.

Basic physical and historical information.

Data tables and historic information.

History, sources, isotopes, and uses.

Physical data, chemical properties, health and environmental effects.

General and physical information, uses, key isotopes, and ionisation energies.

Extensive information on history, uses, occurrence, compounds, and properties of the element.

Explanation with photographs.

Properties of the element, including its history, applications, and characteristics.