Question

An atom of Magnesium usually undergoes covalent bonding with atoms of Chlorine to form a stable compound. false, why?

Answer 1

false.Mg is a group 2 element.and Group two elements generally form compounds which are ionic in nature.\[MgCl _{2} \] with the crystal structure of \[CdCl _{2} \] type.

Answer 2

The chlorine atom is far too electronegative compared to the magnesium atom. So if a covalent bond forms, right away the chlorines will simply steal the electrons in it completely away from the magnesium atoms, and you'll be left with Mg+2 and two Cl- anions.

As for why the Cl is electronegative: it's because the outer shell of the Cl has 7 electrons. That means each electron in the outer shell of a Cl atom feels an effective charge from the nucleus of +7. That's very strong. On the other hand, the outer shell of the Mg atom has 2 electrons, so each electron feels an effective charge of +2, much less. Not surprisingly, if electrons can choose to be floating around the Mg atom or the Cl atom, in the outhermost shell of either, they choose the Cl atom.

Contrast this with carbon, say, which has 4 electrons in the outer shell, so each outer electron feels an effective charge of +4. In this case, while the electrons might prefer to spend more time around the Cl atom, they're not completely averse to spending time near the C atom, which has a pretty heft effective positive charge, too. So C and Cl form polar covalent bonds, in the compound CCl4, in which there are covalent bonds, but they are "biased" (polarized) towards the Cl, so that the electrons in the bonds spend more time near the Cl atom than near the C.