Question

Which of the following is least ionic ?

• A. \( BaCl_2 \)
• B. AgCl
• C. KCl
• D. \( CoCl_2 \)

Answer 1

The Correct Option is B

To determine which compound is the least ionic among the given options, we need to understand the concept of ionic character. The ionic character in a compound largely depends on the difference in electronegativity between the cation and the anion and the size of the ions comprising the compound.

The options provided are:

• \( \text{BaCl}_2 \)
• AgCl
• KCl
• \( \text{CoCl}_2 \)

Let's analyze each option considering the factors that affect ionic character:

1. \( \text{BaCl}_2 \): Barium (Ba) is a Group 2 element, and Chlorine (Cl) is a halogen. The high electronegativity difference results in a strong ionic bond.
2. AgCl: Silver chloride has lower ionic character due to the relatively smaller electronegativity difference between silver (Ag) and chlorine (Cl). Also, silver ions tend to form covalent bonds due to their filled d-orbitals, which reduce the overall ionic character.
3. KCl: Potassium (K) is an alkali metal, and Chlorine (Cl) is a halogen, resulting in a large electronegativity difference and thus, a strong ionic character.
4. \( \text{CoCl}_2 \): Cobalt (Co), a transition metal, forms ionic compounds with halogens. However, due to partial covalent character from its d-orbitals, it might be less ionic than simple alkali or alkaline earth metals, but more ionic than AgCl.

Based on the above analysis, AgCl is the least ionic compound among the given options due to the reasons mentioned, such as closer electronegativity and covalent character contributed by silver's orbital configurations.

Answer 2

To determine which of the given compounds is the least ionic, we need to understand the concept of ionic character. Ionic character is influenced by several factors, including the differences in electronegativity between atoms and the charges on these atoms. Generally, compounds with greater differences in electronegativity between the bonded atoms tend to exhibit greater ionic character. Additionally, the type of ions involved and their ability to polarize each other also play a role.

1. \(BaCl_2\) (Barium Chloride): Barium is an alkaline earth metal, and chlorine is a halogen. The ionic bond between a metal and a halogen is typically quite ionic due to the significant difference in electronegativity.
2. AgCl (Silver Chloride): Silver, being a transition metal, differs from the typical behavior of alkaline or alkali metals. The bond between Ag and Cl is less ionic compared to other metal chlorides due to the smaller difference in electronegativity and the polarizability of Ag⁺ ions.
3. KCl (Potassium Chloride): Potassium is an alkali metal, which typically forms highly ionic compounds with halogens due to the large electronegativity difference.
4. \(CoCl_2\) (Cobalt(II) Chloride): Cobalt is a transition metal. While it has ionic character, the smaller size and higher charge density of Co²⁺ lead to some covalent character due to polarization, but it is still typically more ionic than AgCl.

Among these compounds, AgCl is the least ionic. This is primarily due to the lesser difference in electronegativity between Ag and Cl and the substantial covalent character introduced by the polarization effect of the larger, more polarizable silver cation, Ag⁺. This covalent character decreases the overall ionic characteristic of the compound.