Which compound in each of the following pairs is more ionic?
(d) BCl₃ or AlCl₃

Verified step by step guidance

1. Identify the elements involved in each compound: BCl_3 contains boron (B) and chlorine (Cl), while AlCl_3 contains aluminum (Al) and chlorine (Cl).
2. Recall that ionic character is influenced by the difference in electronegativity between the elements in a compound.
3. Look up the electronegativity values: Boron (B) has an electronegativity of about 2.04, Aluminum (Al) has about 1.61, and Chlorine (Cl) has about 3.16.
4. Calculate the electronegativity difference for each compound: For BCl_3, the difference is |3.16 - 2.04|, and for AlCl_3, the difference is |3.16 - 1.61|.
5. Compare the electronegativity differences: The compound with the greater difference is more ionic.

Key Concepts

Ionic Character

Ionic character refers to the degree to which a bond between two atoms exhibits ionic properties, such as the transfer of electrons from one atom to another. This character is influenced by the difference in electronegativity between the two atoms involved in the bond. A greater difference typically indicates a more ionic bond, as the more electronegative atom attracts the shared electrons more strongly.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. The Pauling scale is commonly used to quantify electronegativity values, with higher values indicating a stronger attraction for electrons. In comparing compounds, the electronegativity of the constituent elements helps determine which compound is more ionic, as larger differences in electronegativity lead to increased ionic character.

Covalent vs. Ionic Compounds

Covalent compounds are formed when atoms share electrons, while ionic compounds are formed when electrons are transferred from one atom to another, resulting in charged ions. The nature of the bonding in a compound can be assessed by examining the elements involved; typically, compounds formed between metals and nonmetals are more ionic, whereas those formed between nonmetals are more covalent. Understanding this distinction is crucial for determining the ionic character of the compounds in question.