Large univalent (1+) Element that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn elements from Group 1 (leftmost column) on the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium or cesium (Cs) and francium (Fr). Note that Lightest and most common element in the universe (~92% by atoms; ~75% by mass). Hydrogen's isotopes are: • 1H (99.9885 %)
• 2H (0.0115 %), also called deuterium.
• 3H, also called Tritium, is a radioactive (t½ = 12.32 y) by-product of atmospheric thermonuclear tests in Earth's hydrosphere and atmosphere.
is not included within the Alkali Metals.
The alkali metals are silvery colored, soft, low Mass of an object divided by its volume. Density is a characteristic property of a substance (rock vs. ice, e.g.). Some substances (like gases) are easily compressible and have different densities depending on how much pressure is exerted upon them. The Sun is composed of compressible gases and is much metals, which react readily with halogens to form ionic salts, and with water to form strongly alkaline (basic) hydroxides. They may be readily fused and volatilized; their melting and boiling points decrease with increasing Mass of a neutral atom of a nuclide - also called "atomic weight." The atomic weight of an element is the weighted average of each isotope.. They are the strongest electropositive metals and react vigorously, even violently, with water.
Some or all content above used with permission from J. H. Wittke.