Magnesium

Element Magnesium

It is a chemical element with the symbol Mg and atomic number 12.
It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure.
Magnesium is the eleventh most abundant element by mass in the human body and is essential to all cells and some 300 enzymes.
Magnesium ions interact with polyphosphate compounds such as ATP, DNA, and RNA. Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives, antacids (e.g., milk of magnesia), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as eclampsia.

Magnesium has three stable isotopes 24 Mg, 25Mg and 26Mg.
All are present in significant amounts (see table of isotopes above). About 79% of Mg is 24Mg. The isotope 28Mg is radioactive and in the 1950s to 1970s was produced by several nuclear power plants for use in scientific experiments.
This isotope has a relatively short half-life (21 hours) and its use was limited by shipping times.