Question

(a) Explain the formation of Calcium Chloride with the help of electron dot structure. (At numbers: Ca = 20; Cl = 17) 

(b) Why do ionic compounds not conduct electricity in solid state but conduct electricity in molten and aqueous state?

Answer 1

(a) Formation of Calcium Chloride with the help of electron dot structure:

1. The molecular formula of Calcium chloride is CaCl₂.
2. The atomic number of Calcium (Ca) is 20.
3. Electronic configuration of Ca is [Ar] 4s² or (2, 8, 8, 2).
4. Hence Calcium needs to lose two electrons to attain noble gas configuration.
5. The atomic number of Chlorine (Cl) is 17.
6. Electronic configuration of Cl is [Ne] 3s²3p⁵ or(2, 8, 7).
7. Hence Chlorine needs to gain one electron to attain noble gas configuration.
8. Therefore, two valence electrons of Calcium form bonds with one electron of each Chlorine, and hence results in the formation of Calcium chloride.

Hence, the Calcium chloride is formed by the combination of one calcium and two chlorine atoms.

(b) Ionic compounds conduct electricity when molten (liquid) or in aqueous solution (dissolved in water), because their ions are free to move from place to place. Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move.

Answer 2

(a)

(b) Ionic compounds do not conduct electricity in solid state due to absence of free ions but they conduct electricity in molten and aqueous state due to presence of free ions.

Comments

The Electronic configuration of Calcium (Ca) is 2,8,8,2.....