Question

Order the following compounds according to the increasing ionic character of their bonds: \(\mathrm{CCl}_{4}, \mathrm{BaCl}_{2}, \mathrm{TiCl}_{3}, \mathrm{ClO}_{2} .\)

Short answer

The order is: ClO extsubscript{2}, CCl extsubscript{4}, TiCl extsubscript{3}, BaCl extsubscript{2}.

Step-by-step solution

Understand Ionic Character

Ionic character is determined by the difference in electronegativity between the atoms in a bond. The greater the difference, the more ionic (less covalent) the bond is.

Identify Electronegativity Values

Find electronegativity values for each of the elements involved in the compounds: - Cl has an electronegativity of 3.16. - Ba has an electronegativity of 0.89. - Ti has an electronegativity of 1.54. - C has an electronegativity of 2.55. - O has an electronegativity of 3.44.

Calculate Electronegativity Differences

Calculate the differences in electronegativity between the atoms in each compound: - For BaCl extsubscript{2}: Ba-Cl has a difference of |3.16 - 0.89| = 2.27. - For TiCl extsubscript{3}: Ti-Cl has a difference of |3.16 - 1.54| = 1.62. - For CCl extsubscript{4}: C-Cl has a difference of |3.16 - 2.55| = 0.61. - For ClO extsubscript{2}: Cl-O has a difference of |3.44 - 3.16| = 0.28.

Order the Compounds by Ionic Character

Arrange the compounds based on the calculated electronegativity differences. The order from least to most ionic character is determined by increasing electronegativity difference. Thus, the order is: 1. ClO extsubscript{2} (0.28) 2. CCl extsubscript{4} (0.61) 3. TiCl extsubscript{3} (1.62) 4. BaCl extsubscript{2} (2.27).

Key concepts

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. It’s a fundamental concept in chemistry because it helps determine how atoms will bond with each other. Electronegativity values are usually given on a scale from 0 to 4, with fluorine being the most electronegative element at 4.0.

When two atoms form a bond, the difference in their electronegativities indicates the bond's nature:

• If the electronegativity difference is small (typically less than 0.5), the bond is generally nonpolar covalent, meaning electronics are shared equally.
• A moderate difference (around 0.5 to 1.7) indicates a polar covalent bond, where electrons are shared unequally.
• A large difference (greater than 1.7) suggests an ionic bond, where electrons are transferred from one atom to another, creating ions.

Understanding these differences is crucial for predicting how chemical compounds will interact and behave.

Covalent Bonds

Covalent bonds form when two atoms share one or more pairs of electrons. This type of bonding typically occurs between nonmetal atoms, which have similar electronegativities. In covalent bonds, the shared electrons allow atoms to fill their outer electron shells, achieving a more stable electron configuration.

The strength of a covalent bond depends on the overlap of the electron orbitals of the bonding atoms. When these orbitals overlap effectively, a strong covalent bond forms. There are further distinctions within covalent bonds:

• Single covalent bonds involve one pair of shared electrons.
• Double covalent bonds involve two pairs of shared electrons.
• Triple covalent bonds involve three pairs of shared electrons.

Polar covalent bonds are a special type of covalent bond with unequal sharing due to different electronegativities, leading to a partial electrical dipole moment. A common example is the bond in a water molecule (H-O). Understanding covalent bonds is vital in studying the structure and function of molecules.

Chemical Compounds

Chemical compounds are substances formed from two or more different elements that are chemically bonded together in fixed proportions. These compounds are represented by chemical formulas that indicate the types and numbers of atoms involved in the compound. For example, water is a chemical compound with the formula \(\mathrm{H}_2\mathrm{O}\), indicating two hydrogen atoms and one oxygen atom.

Compounds can be classified in various ways:

• Molecular compounds are formed by covalent bonds between nonmetal atoms. They often exist as discrete molecules, such as \(\mathrm{CO}_2\).
• Ionic compounds are formed by ionic bonds between metal and nonmetal atoms, resulting in a lattice structure. An example is \(\mathrm{NaCl}\), common table salt.
• Mixed compounds contain both ionic and covalent characteristics.

Understanding the nature of these compounds is essential for predicting chemical reactivity and properties, such as boiling and melting points. Chemical reactions involve the rearrangement of atoms to form new compounds with different properties.

Ionic Bonds

Ionic bonds are a type of chemical bonding arising from the electrostatic attraction between oppositely charged ions. Typically, these bonds form between metal and nonmetal atoms where one atom (usually the metal) loses electrons to become a positively charged cation, while another (usually the nonmetal) gains those electrons to become a negatively charged anion. This transfer of electrons results in the creation of ions.

The signature feature of ionic compounds is their crystalline lattice structure. This structure contributes to their high melting and boiling points. In aqueous solutions, ionic compounds often dissolve by dissociating into their individual ions, which can conduct electricity.

To predict when an ionic bond will form, the difference in electronegativity between the involved atoms is crucial. A difference greater than 1.7 often indicates an ionic bond. Ionic bonds are primarily strong because of the attraction between the oppositely charged ions. This understanding is key to explaining many macroscopic properties like solubility, hardness, and electrical conductivity.