 |
Periodic Table of the Elements Click on the elements to obtain detailed information on that particular element.
Legend Alkali metals Soft compared to other metals, have low melting points, and are so reactive that they are never found in nature uncombined with other elements. They are powerful reducing agents, that is, they give up an electron easily, and react violently with water to form hydrogen gas and hydroxides, or strong bases. Alkaline earth metals They are strong reducing agents, that is, they give up electrons easily. They are less reactive than the alkali metals, but reactive enough not to be found free in nature. Although rather brittle, the alkaline earth metals are malleable and extrudable. They conduct electricity well, and when heated, burn readily in air. Their oxides are called alkaline earths. Transition metals The transition elements have such typical metallic properties as malleability, ductility, high conductivity of heat and electricity, and metallic luster. They tend to act as reducing agents (donors of electrons), but are less active in this regard than the alkali metals and alkaline earth metals, which have valences of +1 and +2, respectively. Transition elements in general have high densities and melting points and exhibit magnetic properties. They form both ionic and covalent bonds with anions (negatively charged ions), and such compounds are in general brightly colored. Lanthanide series Also known as Rare Earth Elements or Rare Earth Metals. Chemically, most of the rare earth elements are trivalent. Cerium alone forms compounds with a valence of +4. Most rare earth compounds are strongly paramagnetic. An alloy composed of iron and of rare earth metals, called misch metal, is pyrophoric. When scratched it gives off sparks capable of igniting flammable gases. It is used in cigarette lighters, miners' safety lamps, and automatic gas-lighting devices. Misch metal is also used in making aluminum and magnesium alloys and some types of steel. Europium is used as a phosphor activator. In a color television tube it provides the red color seen by the viewer. Actinide series Only the first four elements in the series have been found in nature in appreciable amounts; the remainder have been produced synthetically. Those elements with atomic numbers of 93 and above are called transuranium elements. Other metals Other metals Other nonmetals Other nonmetals Noble gases Under ordinary conditions as colourless, odourless, tasteless, nonflammable gases.
They traditionally have been labelled Group 0 in the periodic table because for decades after their discovery it was believed that they had a valence of zero; that is, that their atoms could not combine with those of other elements to form chemical compounds.
Sources:
Microsoft Encarta 98
Encyclopedia Britannica, 1999
