Question

Arrange the following oxides in order of increasing ionic character: \(\mathrm{SiO}_{2}, \mathrm{~K}_{2} \mathrm{O}, \mathrm{P}_{4} \mathrm{O}_{10}, \mathrm{Ga}_{2} \mathrm{O}_{3}, \mathrm{GeO}_{2}\).

Short answer

The order is: P₄O₁₀, GeO₂, SiO₂, Ga₂O₃, K₂O.

Step-by-step solution

Understand Ionic Character

Ionic character is determined by the difference in electronegativity between the constituent elements of the compound. The greater the difference, the more ionic the compound is, with metal oxides usually being more ionic than non-metal oxides.

Identify Component Elements

Examine each oxide and identify which elements are involved: Si in SiO₂, K in K₂O, P in P₄O₁₀, Ga in Ga₂O₃, and Ge in GeO₂. The oxygen remains constant in all these compounds.

Determine Electronegativity Differences

Use a periodic table to find the electronegativities: Si (≈1.9), K (≈0.8), P (≈2.1), Ga (≈1.6), Ge (≈2.0), and O (≈3.5). Calculate the difference for each oxide: SiO₂ (1.6), K₂O (2.7), P₄O₁₀ (1.4), Ga₂O₃ (1.9), and GeO₂ (1.5).

Rank Based on Ionic Character

Order the oxides from least to most ionic based on their electronegativity difference: P₄O₁₀ (1.4), GeO₂ (1.5), SiO₂ (1.6), Ga₂O₃ (1.9), K₂O (2.7).

Final Order

The final order of increasing ionic character is: P₄O₁₀, GeO₂, SiO₂, Ga₂O₃, K₂O.

Key concepts

Electronegativity

Electronegativity is a chemical property that describes the ability of an atom in a molecule to attract shared electrons towards itself. It's a crucial factor in determining how atoms in a compound will interact with each other. The difference in electronegativity between the atoms in a compound plays a vital role in defining the compound’s ionic or covalent nature. For example, in the given oxides like K₂O or SiO₂, knowing the electronegativities helps us predict their behavior. - Oxides with a large electronegativity difference between their constituents, such as K₂O (potassium oxide), form more ionic bonds. Potassium (K) has a low electronegativity around 0.8, while oxygen (O) has a high electronegativity of 3.5, thus creating a significant difference. - Smaller electronegativity differences lead to more covalent characteristics. To calculate textbook examples of electronegativity differences, subtract the smaller value from the larger one. The greater this difference, the more ionic the bond. In summary, understanding electronegativity is key to predicting how different elements will bond and the nature of the compounds they form.

Metal Oxides

Metal oxides are compounds composed of metal elements bonded to oxygen. These oxides typically form ionic bonds, especially when the metal is highly reactive. They are usually solid at room temperature and often have the properties of bases in a chemical reaction. Common characteristics include:

• High melting and boiling points, due to strong ionic bonds.
• Tendency to react with acids to produce salts and water, displaying basic properties.
• Many metal oxides dissolve in water to form alkaline solutions.

For instance, K₂O (potassium oxide) is a metal oxide with one of the highest ionic characters in the given list. With a significant difference in electronegativity between K and O, it forms strong ionic bonds. Metal oxides play a significant role in industrial chemical processes and in understanding their ionic character can help predict their reactivity and use in various reactions.

Non-metal Oxides

Non-metal oxides consist of non-metal elements chemically bonded to oxygen. These types of oxides generally exhibit covalent bonding and are often gases or liquids at room temperature. In chemical reactions, they tend to behave as acids, particularly when they dissolve in water. Key features of non-metal oxides include:

• Lower melting and boiling points than metal oxides because of molecular covalent bonds.
• Tendency to react with bases to form salts and water, highlighting their acidic nature.
• Generally, do not conduct electricity, as they lack free ions or electrons.

In the context of the exercise, SiO₂ (silicon dioxide) presents a less ionic character compared to many metal oxides, demonstrating typical features of a non-metal oxide. It forms strong covalent bonds, resulting in its structure as a solid rather than a gas. Understanding the behavior of non-metal oxides provides insights into their interactions in natural processes and industrial applications, such as in the creation of materials like glass or in atmospheric chemistry.