Information about the element, Fluorine, atomic number 9. Covers physical and atomic properties, how abundant it is on the Earth, and permissible exposure limits. Also discusses uses, isotopes, and health concerns.

Information about the element, Europium, atomic number 63. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element, Erbium, atomic number 68. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element, Curium, atomic number 96. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element, Copper, atomic number 29. Covers its history, sources, physical properties, atomic properties, how abundant it is on the Earth, details about permissible exposure, uses, and possible substitutes.

Information about the element, Cobalt, atomic number 27. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations, and its importance to human and to animal health. Also...

Information about the element, Chromium, atomic number 24. Covers discovery, physical and atomic properties, how abundant it is on the Earth, permissible exposure limits, sources, uses, and potential substitutes.

Information about the element, Chlorine, atomic number 17. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element, Cerium, atomic number 58. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element, Cadmium, atomic number 48. Covers physical and atomic properties, how abundant it is on the Earth, sources, its presence in the environment, uses, substitutes, and health considerations.

Information about the element, Bromine, atomic number 35. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations. Discusses sources, uses, and substitutes.

Information about the semi-metallic element, Boron, atomic number 5. Covers physical and atomic properties, how abundant it is on the Earth, sources, uses, and possible substitutes.

Information about the element, Beryllium, atomic number 4. Covers physical and atomic properties, how abundant it is on the Earth, sources, uses, and permissible exposure limits.

Information about the element, Berkelium, atomic number 97. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Basic information about the element, Barium, atomic number 56. Covers physical and atomic properties, how abundant it is on the Earth, and permissible exposure limits.

Basic information about the element Arsenic, atomic number 33. Covers physical properties and properties, sources, how abundant it is on the Earth, uses, and toxicity.

Information about the element, Argon, atomic number 18. Covers physical and atomic properties, how abundant it is on the Earth, its history, isotopes, uses, and health considerations.

Information about the element, Americium, atomic number 95. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations.

Information about the element Zirconium, atomic number 40. Covers history of its discovery, sources, physical properties, atomic properties, how abundant it is on the Earth, details about permissible exposure, uses, and possible...

Information about the element, Zinc, atomic number 30. Covers physical and chemical properties, how abundant it is on the Earth, where it occurs, isotopes, zinc in the environment, its role in human health, and the history of its use in...

Information about the element, Silicon, atomic number 14. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about health-related regulations. Also discusses sources of Silicon, and its many...

Article describing the Proterozoic Eon, which lasted from 2.5 billion to 543 million years ago. It covers the subdivisions of the Proterozoic Eon, geology, Earth's atmosphere at the time, climate, and life forms. (Published: July 26, 2010)

Information about the heavy metal, Lead, atomic number 82. Gives some interesting historical details about lead's use in the past. Covers physical properties, atomic properties, how abundant it is on the Earth, and details about...

Information about the element, Calcium, atomic number 20. Covers physical and atomic properties, sources, its role in geochemical cycles, how abundant it is on the Earth, its isotopes, some compounds of calcium, and its importance to...