DEFINITION: The artifacts and ecofacts used by a group to cope with their physical and social environment. Material culture includes the buildings, tools, and other artifacts that constitute the material remains of a former society -- its technology and artifacts combined.
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth 's crust. The ion Ca 2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.alcium salts are colorless from any contribution of the calcium, and ionic solutions of calcium (Ca 2+) are colorless as well. As with magnesium salts and other alkaline earth metal salts, calcium salts are often quite soluble in water.
A calcium atom becomes a calcium ion by losing two electrons. Electrons are negatively charged, so losing two electrons creates an ion with a charge of 2+. According to the octet rule, atoms gain or lose electrons to fill their outer energy levels. This helps them achieve noble gas configuration. Calcium is atomic number 20 on the periodic table. Its nearest noble gas is argon, which has an atomic number of 18. To achieve argon's electron configuration, calcium needs to lose two electrons. When it does this, it becomes a positively charged ion. Although calcium is in the same period as the noble gas krypton, the calcium never attempts to attain krypton's electron configuration. This is because it takes less energy to lose two electrons than it would to gain six electrons and fill the outer energy level.