Question

which statement correctly explains how magnesium and chlorine combine to form magnesium chloride? 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.

Answer 1

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

Explanation: Ionic compound is formed by transfer of electrons from metal to non metal.

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

Here magnesium is metal with atomic number 12 and chlorine is a non metal with atomic number of 17.

$Mg:12:1s^22s^22p^63s^2$

$Mg^{2+}:10:1s^22s^22p^6$

$Cl:17:1s^22s^22p^63s^23p^5$

$Cl^-:18:1s^22s^22p^63s^23p^6$

Thus magnesium loses two electrons to form $Mg^{2+}$ and chlorine atoms gain one electron each to form $Cl^-$

Thus the compound formed is $MgCl_2$.

Answer 2

Answer: Option (D) is the correct answer.

Explanation:

As the atomic number of magnesium is 12 and its electronic distribution is 2, 8, 2. Hence, in order to attain stability magnesium will readily lose its valence electrons.

Therefore, magnesium will form a $Mg^{+2}$ ion.

Whereas atomic number of chlorine is 17 and its electronic distribution is 2, 8, 7. And, in order to attain stability it will readily accept an electron from a donor atom.

Hence, on gaining one electron a neutral atom of Cl will convert into $Cl^{-}$ ion.

Therefore, magnesium chloride ($MgCl_{2}$) is the compound formed when both magnesium and chlorine chemically react with each other.

Thus, we can conclude that the statement Mg atom donates one electron to each of the two Cl atoms, correctly explains how magnesium and chlorine combine to form magnesium chloride.