Draw a Lewis diagram to show the formation of the ionic compound barium chloride (BaCl2)
The Correct Answer and Explanation is:
Lewis Diagram for the Formation of Barium Chloride (BaCl₂):
Here’s a simplified representation of the Lewis diagram:
Ba •• + ••Cl•• + ••Cl••
↓ ↓ ↓
[Ba]²⁺ + [:Cl:]⁻ + [:Cl:]⁻
Explanation
Barium chloride (BaCl₂) is an ionic compound formed by the transfer of electrons from a metal (barium) to a non-metal (chlorine). To understand this, we use Lewis diagrams, which represent the valence electrons of atoms and illustrate how they are involved in bond formation.
Barium (Ba) is an alkaline earth metal found in group 2 of the periodic table. It has two valence electrons, which it readily loses to achieve a stable electron configuration similar to the noble gas xenon. In losing two electrons, barium becomes a Ba²⁺ ion.
Chlorine (Cl) is a halogen in group 17 and has seven valence electrons. It needs one more electron to complete its octet and become stable, forming a Cl⁻ ion when it gains one electron.
In the formation of BaCl₂, each chlorine atom gains one electron. Since barium loses two electrons, two chlorine atoms are required to accept these two electrons. This results in the formation of one Ba²⁺ ion and two Cl⁻ ions. The positively charged barium ion and the negatively charged chloride ions attract each other due to electrostatic forces, forming an ionic bond.
In the Lewis diagram:
- The barium atom is shown with its two valence electrons, which are transferred (indicated by arrows) to two chlorine atoms.
- Each chlorine atom originally has seven valence electrons (three lone pairs and one unpaired electron) and gains one electron from barium, completing their octet.
- The resulting ions are shown in brackets, with charges indicated: [Ba]²⁺ and [:Cl:]⁻.
- This shows that barium chloride is formed by the transfer of electrons and the attraction between oppositely charged ions.
This ionic bonding is responsible for the high melting point and crystalline structure of BaCl₂.;
