alkaline-earth metals
alkaline-earth metals,
metals constituting Group 2 of the periodic tableperiodic table,chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
..... Click the link for more information. . Generally, they are softer than most other metals, react readily with water (especially when heated), and are powerful reducing agents, but they are exceeded in each of these properties by the corresponding alkali metal. They form divalent compounds. In order of increasing atomic number the alkaline-earth metals are berylliumberyllium
[from beryl ], metallic chemical element; symbol Be; at. no. 4; at. wt. 9.01218; m.p. about 1,278°C;; b.p. 2,970°C; (estimated); sp. gr. 1.85 at 20°C;; valence +2.
..... Click the link for more information. , magnesiummagnesium
, metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.3050; m.p. about 648.8°C;; b.p. about 1,090°C;; sp. gr. 1.738 at 20°C;; valence +2. In 1808, Sir Humphry Davy discovered magnesium in its oxide, although it is not certain that he isolated the
..... Click the link for more information. , calciumcalcium
[Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.078; m.p. about 839°C;; b.p. 1,484°C;; sp. gr. 1.55 at 20°C;; valence +2. Calcium is a malleable, ductile, silver-white, relatively soft metal with face-centered, cubic crystalline
..... Click the link for more information. , strontiumstrontium
[from Strontian, a Scottish town], a metallic chemical element; symbol Sr; at. no. 38; at. wt. 87.62; m.p. 769°C;; b.p. 1,384°C;; sp. gr. 2.6 at 20°C;; valence +2.
..... Click the link for more information. , bariumbarium
[Gr.,=heavy], metallic chemical element; symbol Ba; at. no. 56; at. wt. 137.327; m.p. 725°C;; b.p. 1,640°C;; sp. gr. 3.5 at 20°C;; valence +2. Barium is a soft, silver-white, chemically active, poisonous metal with a face-centered cubic crystalline structure.
..... Click the link for more information. , and radiumradium
[Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; mass number of most stable isotope 226; m.p. 700°C;; b.p. 1,140°C;; sp. gr. about 6.0; valence +2. Radium is a lustrous white radioactive metal.
..... Click the link for more information. .
alkaline-earth metals
[¦al·kə‚līn ′ərth ′med·əlz] (chemistry)
The heaviest members of group 2 in the periodic table; usually calcium, strontium, magnesium, and barium.