Which Atom experiences a greater shielding effect, Magnesium (Mg) or chlorine (CI)?

To be stable, an atom or ion should have 8 electrons in the outer shell. This is called the octet rule.

Magnesium is unstable because a magnesium atom has 2 valance electrons in its 3rd shell.

Chlorine is unstable, because a chlorine atom has 7 valance electrons is its 3rd shell.

Chlorine has higher electronegativity than magnesium, so the 2 chlorine atoms will attract 2 electrons from a magnesium atom. This produces a +2 magnesium ion and two -1 chloride ions.

A) A Cl atom donates two electrons to a Mg atom  

B) An Mg atom donates two electrons to a Cl atom.  

C) A Cl atom donates one electron to each of the two Mg atoms.  

D) An Mg atom donates one electron to each of the two Cl atoms. YES

Atoms do not donate any electrons. When a chlorine molecule collides with a magnesium atom, each of the chlorine atoms grab an electron from the outer shell of the magnesium atom. You might think that the magnesium atom would be angry at the chlorine molecule. But, the magnesium atom is much “happier” as a stable +2 ion than a neutral atom. And the chlorine molecule is also “happier” as two -1 chloride ions.

Magnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2(H2O)x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water. Magnesium chloride as the natural mineral bischofite is also extracted (solution mining) out of ancient seabeds; for example, the Zechstein seabed in northwest Europe. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form usually used in prescription oral magnesium supplements.

We are the ones who messed with mother nature. Magnesium chloride was very stable (happy) when it was in the sea water. Humans decided to harvest the MgCl2 and rip it apart to produce little strips of magnesium metal for chemistry class.

In nature, “nobody” freely donates anything to “anyone”. The electrostatic forces in the atoms decide who get the electons.

Sometimes, I just get carried away as I answer peoples’ question.

I hope this helped you.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%