Question

State the type of bonding -ionic, covalent, or metallicyou would expect in each: (a) \(\mathrm{ICl}_{3}(g)\) (b) \(\mathrm{N}_{2} \mathrm{O}(g)\) (c) \(\mathrm{LiCl}(s)\)

Short answer

(a) Covalent (b) Covalent (c) Ionic

Step-by-step solution

Identify the Bonding in \(\text{ICl}_3\) - Step 1

Determine the electronegativity difference between iodine (I) and chlorine (Cl). Both are nonmetals and relatively close in electronegativity on the periodic table, so the bonding is primarily covalent.

Identify the Bonding in \(\text{N}_2\text{O}\) - Step 2

Analyze the bond between nitrogen atoms (N) and oxygen (O). Both are nonmetals. Nitrogen and oxygen bond covalently due to their close electronegativity values and the sharing of electrons.

Identify the Bonding in \(\text{LiCl}\) - Step 3

Examine the bond between lithium (Li) and chlorine (Cl). Lithium is a metal and chlorine is a nonmetal. The significant difference in electronegativity between Li and Cl leads to ionic bonding.

Key concepts

Ionic Bonding

Ionic bonding occurs when atoms transfer electrons from one to another. This results in the formation of ions: one atom becomes a positively charged cation, and the other becomes a negatively charged anion. These opposite charges attract each other, creating a strong electrostatic force known as an ionic bond.

In ionic compounds, we typically see this bonding between metals and nonmetals. For example:

• In \(\text{LiCl}\), lithium (a metal) donates an electron to chlorine (a nonmetal), forming \(\text{Li}^{+}\) and \(\text{Cl}^{-}\) ions.

Ionic bonds tend to form crystalline structures with high melting and boiling points due to the strength of the ionic attractions.

This type of bonding is strongest when the difference in electronegativity between the two atoms is significant.

Covalent Bonding

Covalent bonding happens when two atoms share one or more pairs of electrons. This usually occurs between nonmetals with similar electronegativity values.

For instance:

• In \(\text{ICl}_3\), both iodine and chlorine are nonmetals with nearly equal electronegativity, causing them to share electrons and form a covalent bond.
• In \(\text{N}_2\text{O}\), nitrogen and oxygen share electrons to achieve a stable electron configuration, resulting in covalent bonds.

Covalent bonds can be single (\text{e.g.,} \(\text{H}_2\)), double (\text{e.g.,} \(\text{O}_2\)), or triple (\text{e.g.,} \(\text{N}_2\)). The strength and stability of the bond increase with the number of shared pairs.

Covalent compounds exhibit varied properties, such as lower melting and boiling points, compared to ionic compounds.

Electronegativity Difference

Electronegativity is a measure of how strongly an atom attracts electrons in a bond. The difference in electronegativity values between two bonding atoms helps determine the bond type.

When the electronegativity difference is:

• Large (typically \(\triangle EN > 2.0\)): The bond is usually ionic, with one atom effectively transferring an electron to another.
• Moderate (0.4 < \( \triangle EN \leq 2.0\)): The bond is polar covalent, where electrons are shared but not equally. The atom with higher electronegativity pulls the shared electrons closer.
• Small (\( \triangle EN \leq 0.4 \)): The bond is nonpolar covalent, with equal or nearly equal sharing of electrons.

Understanding electronegativity differences is crucial. It explains why \( \text{LiCl} \) forms an ionic bond (large difference) and why \( \text{ICl}_3 \) and \( \text{N}_2\text{O} \) form covalent bonds (small difference).