the symbol is Mg, the atomic number is 12 and the common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust, where it constitutes about 2% by mass , and ninth in the known Universe as a whole. This preponderance of magnesium is related to the fact that it is easily built up in supernova stars from a sequential addition of three helium nuclei to carbon (which in turn is made from three helium nuclei). Magnesium ion's high solubility in water helps ensure that it is the third most abundant element dissolved in seawater.
Magnesium is the 11th most abundant element by mass in the human body; its ions are essential to all living cells, where they play a major role in manipulating important biological polyphosphate compounds like ATP, DNA, and RNA. Hundreds of enzymes thus require magnesium ions in order to function. Magnesium is also the metallic ion , and is thus a common additive to fertilizers. Magnesium compounds are used medicinally as common laxatives, antacids (i.e., milk of magnesia ), and in a number of situations where stabilization of abnormal nerve excitation and blood vessel spasm is required (i.e., to treat ecamplasia ). Magnesium ions are sour to the taste, and in low concentrations help to impart a natural tartness to fresh mineral waters.
2. Avogadro's hypothesis
It's amazing how Avogadro discovered that the equal volumes of gas , at the same pressure and temperature , include the equal numbers of molecules is amazing. Moreover it is amazing that it took fifty years before Avogadro's work was recognized. It was also surprising that Avogadro made the distinction between atoms and molecules and again was pushed into the dark recesses of chemistry libraries and ignored.
3. What is a mole ? the amount of substance of a system that contains as many elementary entities such as atoms, molecules, ions and electrons.
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