Matter & Energy

Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Alkaline Earth Metals

Alkaline Earth Metals, series of six chemical elements in group 2 (or IIa) of the periodic table (see Periodic Law). 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. The alkaline earth metals are, in order of increasing atomic number, beryllium, magnesium, calcium, strontium, barium, and radium. Their oxides are called alkaline earths.