Ca-EDTA is more stable.. its stability constant is above 10 wheras Mg's is below 9, as to why this is I dont know
lose two elcetrons
Silver nitrate is more stable.
Calcium is more reactive but not as Potassium or Sodium because according to the displacement series Calcium comes as third and the last under the reactive elements of the displacement series.
Zinc has more electrons in its outer energy level than Calcium. Because of this, itsnucleus is more attracted to this energy level and pulls it more the nucleus in Calcium. Because of this greater attraction it is harder to remove the electron from Zinc.
Magnesium oxide is at a lower energy state than lead oxide, which makes it more stable, more likely to form. So this additional energy is released as heat.
Replacement Titration: In this method the metal, which is to be analyzed, displaces quantitatively the metal from the complex. When direct or back titrations do not give sharp end points, the metal may be determined by the displacement of an equivalent amount of Mg or Zn from a less stable EDTA complex. Mn+2 + Mg EDTA---> 2 Mg+2 + Mn EDTA-2 Mn displaces Mg from Mn EDTA solution. The freed Mg metal is then directly titrated with a standard EDTA solution. In this method, excess quantity of Mg EDTA chelate is added to Mn solution. Mn quantitatively displaces Mg from Mg EDTA chelate. This displacement takes place because Mn forms a more stable complex with EDTA. By this method Ca, Pb, Hg may be determined using Eriochrome blackT indicator.
DPBS- Formulated by Dulbecco, Complete DPBS contians Calcium and magnesium. PBS- Which is used to wash the cells before trypsinization do not have calcium and magnesium and may have additional EDTA also. Typically there are many more combinations of Balanced salt solutions, So go by the formulations not by the name.
As calcium is more reactive than magnesium calcium will displace the magnesium and will become calcium nitrate and is left over with magnesium on it's own
Magnesium
Calcium is more reactive than magnesium because it is larger than a magnesium atom because it has one more energy level. Valence electrons are on the outermost occupied energy level in the atom and they cause the atom to react, and thus the further the Valence electrons are from the nucleus, the more reactive they are. Therefore, calcium is more reactive than magnesium because the valence electrons on the calcium atom is farther from the nucleus.
The indicator added to the sample is Eriochrome Black T. Initially, the indicator will form a complex with the cations. When complexed it is red in color. As the EDTA is added dropwise to the sample, it replaces the Erio T and forms more stable complexes with calcium and magnesium. When the indicator is released by the metal ions, it has a distinct blue color. Therefore, the endpoint of the titration is marked by the color change form red to blue
Liquid calcium magnesium is a combination of two important minerals in a more easily absorbed form. There is information on the pros and cons of using liquid calcium magnesium on the LIVESTRONG website.
Chemistry of calcium Calcium is generally more reactive than magnesium
Calcium reacts more easily with water than does magnesium, because calcium donates electrons to other elements more readily than magnesium, as expected for a larger atom in the same periodic table column on the left side of a wide form periodic table.
calcium and mg are more reactive
Because its ionic bonds between magnesium and oxygen are stronger and more stable than the metallic bonds between magnesium and the covalent bonds between oxygen
Calcium nitrate and magnesium will not react since calcium is more reactive than magnesium and so, magnesium does not displace calcium (See Reactivity Series). However, if Calcium nitrate is in aqueous solution (dissolved in water), some bubbles may be seen when Magnesium is added to it, since the Magnesium would be reacting with the water and producing hydrogen bubbles.