Atomic symbol: Dy Atomic weight: 162.500
Atomic number: 66
Electron configuration: 2-8-18-28-8-2
Oxidation states: +3
State of matter: solid
Heavy metal, brittle
Discovered in 1886 by P.É. Lecoq de Boisbaudran
Boils at 2335°C, melts at 1409°C
A hard and reactive metal, dysprosium has few uses. Its compounds can be used as catalysts in oil refining, and as components in some electronics. Near absolute zero, dysprosium is superconducting.
Atomic symbol: Er Atomic weight: 67.259
Atomic number: 68
Electron configuration: 2-8-18-30-8-2
Oxidation states: +3 State of matter: solid Heavy metal, brittle
Discovered in 1843 by C.G. Mosander Boils at 2510°C, melts at 1522°C
Erbium is a metal with few uses. It is a grayish- silver color and can be used as an infrared absorbing glass and as an activator in some phosphorescent materials.
Atomic symbol: F
Atomic weight: 18.9984032
Atomic number: 9
Electron configuration: 2-7
Oxidation states: -1 State of matter: gas Non-metal
Discovered in 1886 by Henri Moissan Boils at -188°C, freezes at -220°C
Fluorine is the most active member of the halogen family, and produces the most stable compounds. It is very poisonous because of its great activity. It is so active that it is not found free in nature, only in a combined state, and is very abundant. It occurs as either the mineral fluorine, or the mineral cryolite. Freon, the refrigerant, contains fluorine. Cryolite, or sodium aluminum fluoride, is an important flux in the electrolytic production of aluminum metal. Compounds of fluorine and carbon are important because of their heat and fire resistance. Fluorine is found in tap water and toothpaste, which had beneficial effects on teeth. Other fluorine compounds are used as insecticides and wood preservatives.