Question

Predict whether each of the following oxides is ionic or molecular. \(\mathrm{SO}_{2}, \mathrm{MgO}, \mathrm{Li}_{2} \mathrm{O}, \mathrm{P}_{2} \mathrm{O}_{5}, \mathrm{Y}_{2} \mathrm{O}_{3}, \mathrm{~N}_{2} \mathrm{O}\), and \(\mathrm{XeO}_{3}\) Explain the reasons for your choices.

Short answer

The ionic oxides are: \(\mathrm{MgO}\), \(\mathrm{Li}_{2} \mathrm{O}\), and \(\mathrm{Y}_{2} \mathrm{O}_{3}\), while the molecular oxides are: \(\mathrm{SO}_{2}\), \(\mathrm{P}_{2} \mathrm{O}_{5}\), \(\mathrm{N}_{2} \mathrm{O}\), and \(\mathrm{XeO}_{3}\). This categorization is based on the types of elements involved in each oxide: ionically bonded substances are formed when a metal reacts with a non-metal, and molecular (covalently bonded) substances are formed between non-metals.

Step-by-step solution

Identify the types of elements in each oxide

: Before categorizing each oxide as ionic or molecular, we need to recognize the types of elements involved. We can refer to the periodic table to determine whether the elements are metals or non-metals. 1. \(\mathrm{SO}_{2}\) : Sulfur (non-metal) and Oxygen (non-metal) 2. \(\mathrm{MgO}\) : Magnesium (metal) and Oxygen (non-metal) 3. \(\mathrm{Li}_{2} \mathrm{O}\) : Lithium (metal) and Oxygen (non-metal) 4. \(\mathrm{P}_{2} \mathrm{O}_{5}\) : Phosphorus (non-metal) and Oxygen (non-metal) 5. \(\mathrm{Y}_{2} \mathrm{O}_{3}\) : Yttrium (metal) and Oxygen (non-metal) 6. \(\mathrm{N}_{2} \mathrm{O}\) : Nitrogen (non-metal) and Oxygen (non-metal) 7. \(\mathrm{XeO}_{3}\) : Xenon (non-metal) and Oxygen (non-metal)

Determine the type of bonding and categorize as ionic or molecular

: Now that we have identified the types of elements in each oxide, we can determine the type of bonding and categorize each as either ionic or molecular. 1. \(\mathrm{SO}_{2}\) : Sulfur (non-metal) and Oxygen (non-metal) - Covalent bonding (molecular) 2. \(\mathrm{MgO}\) : Magnesium (metal) and Oxygen (non-metal) - Ionic bonding (ionic) 3. \(\mathrm{Li}_{2} \mathrm{O}\) : Lithium (metal) and Oxygen (non-metal) - Ionic bonding (ionic) 4. \(\mathrm{P}_{2} \mathrm{O}_{5}\) : Phosphorus (non-metal) and Oxygen (non-metal) - Covalent bonding (molecular) 5. \(\mathrm{Y}_{2} \mathrm{O}_{3}\) : Yttrium (metal) and Oxygen (non-metal) - Ionic bonding (ionic) 6. \(\mathrm{N}_{2} \mathrm{O}\) : Nitrogen (non-metal) and Oxygen (non-metal) - Covalent bonding (molecular) 7. \(\mathrm{XeO}_{3}\) : Xenon (non-metal) and Oxygen (non-metal) - Covalent bonding (molecular) So, the ionic oxides are: \(\mathrm{MgO}\), \(\mathrm{Li}_{2} \mathrm{O}\), and \(\mathrm{Y}_{2} \mathrm{O}_{3}\), while the molecular oxides are: \(\mathrm{SO}_{2}\), \(\mathrm{P}_{2} \mathrm{O}_{5}\), \(\mathrm{N}_{2} \mathrm{O}\), and \(\mathrm{XeO}_{3}\).

Key concepts

Chemical Bonding

Chemical bonding is the fundamental concept that explains how atoms join together to form compounds. Atoms can bond in several ways, but the two main types are ionic and covalent bonding.

Ionic bonding occurs between a metal and a non-metal. Metals, which tend to lose electrons, are called cations, while non-metals, which gain those electrons, become anions. The electrostatic forces of attraction between oppositely charged ions lead to the formation of an ionic compound. A classic example is table salt (sodium chloride, NaCl), where sodium (Na) loses an electron to become Na⁺ and chlorine (Cl) gains an electron to become Cl⁻. The result is a crystal lattice of Na⁺ and Cl⁻ ions held together by ionic bonds.

Covalent bonding, on the other hand, involves the sharing of electrons between non-metal atoms. This type of bond results in the formation of a molecule. The shared electrons allow each non-metal atom to achieve a stable electron configuration. Water (H₂O) is a familiar example; oxygen shares electrons with two hydrogen atoms, making H₂O a molecular compound.

Periodic Table

The periodic table is a tabular arrangement of the chemical elements, organized by their atomic number, electron configuration, and recurring chemical properties. It's divided into periods (horizontal rows) and groups (vertical columns). Elements are generally classified into metals, non-metals, and metalloids.

Metals, found on the left side and in the center of the periodic table, are typically shiny, malleable, and good conductors of heat and electricity. Non-metals, located on the right side of the table, are diverse; they can be gases, like oxygen or fluorine, or solids, like carbon and sulfur, and they're usually poor conductors of heat and electricity. Metalloids, such as silicon and germanium, have properties that are intermediate between metals and non-metals.

Understanding the periodic table is crucial for predicting the types of chemical bonding that can occur between elements, thereby allowing us to predict whether a compound is likely to be ionic or molecular based on the positions of its constituent elements on the periodic table.

Metal and Non-Metal Chemistry

The chemistry of metals and non-metals is diverse due to their contrasting properties. Metals tend to give up electrons to achieve a stable electron configuration, whereas non-metals tend to gain or share electrons.

When metals react with non-metals, they typically form ionic compounds. For instance, magnesium oxide (MgO) is an ionic compound comprised of Mg²⁺ and O²⁻ ions. In these compounds, the metal atoms become positively charged ions, while the non-metal atoms become negatively charged ions.

In contrast, non-metals react with each other to form molecular compounds through covalent bonding. For example, carbon dioxide (CO₂) is a molecular compound where each oxygen atom shares four electrons with a carbon atom, resulting in double bonds.

Understanding the differences in chemical behavior between metals and non-metals helps us to predict the properties of compounds they form and their reactivity among each other. This prediction is particularly useful when dealing with oxides, which can be broadly categorized depending on whether they are formed with metals or non-metals.