Chapter 7: Problem 78
How do the chemical properties of oxides change from left to right across a period? How do they change from top to bottom within a particular group?
Short Answer
Expert verified
Across a period, oxides shift from basic to acidic; down a group, they become more basic.
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Chemical Properties of Oxides
Oxides are compounds that consist of oxygen and another element. These compounds play a crucial role in chemistry, and their properties vary significantly across the periodic table.
When examining the periodic table, one notable trend is how the chemical properties of oxides change as you move across a period or down a group. From left to right across a period, elements shift from metals to nonmetals. Metals typically form basic oxides, which react with water to produce hydroxides, contributing to an alkaline solution. As you proceed towards the right, the oxides transition to acidic, which often combine with water to form acids due to the dominance of nonmetallic character.
Conversely, when moving down a group, the trend for oxides is to become more basic. This is because the metallic nature of the elements increases. For students, it's important to note that these trends significantly affect how oxides will react in chemical processes, influencing reactions like neutralization.
Metallic and Nonmetallic Character
The metallic and nonmetallic character of elements is a fundamental concept that describes how elements tend to behave. This characteristic can be directly linked to an element’s position on the periodic table.
- **Metallic Character:**
- Elements on the left side of the periodic table exhibit metallic characteristics.
- They tend to lose electrons easily during reactions, forming positive ions or cations.
- Such elements often have shiny appearances, are good conductors of electricity, and have high melting and boiling points.
- **Nonmetallic Character:**
- Elements on the right side, including those in groups like the halogens or noble gases, show nonmetallic properties.
- These tend to gain electrons during chemical reactions, forming negative ions or anions.
- Nonmetals typically have dull appearances, are poor conductors, and usually possess lower melting and boiling points.
The transition from metallic to nonmetallic character occurs across a period, explaining the change in chemical properties, including those of oxides, from basic to acidic.
Basic and Acidic Oxides
Oxides can be broadly categorized into basic, acidic, or amphoteric based on how they react with water or acids. Understanding these types of oxides is essential for grasping their role in chemistry.- **Basic Oxides:** - Formed mainly by metals, these oxides react with water to create hydroxides, which are alkaline. - Example: Sodium oxide \( \text{Na}_2\text{O} + \text{H}_2\text{O} \rightarrow 2\text{NaOH} \) - They are more prevalent on the left side of the periodic table, with basicity decreasing as you move to the right.- **Acidic Oxides:** - Formed predominantly by nonmetals, these oxides react with water to form acids. - Example: Sulfur dioxide \( \text{SO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{SO}_3 \) - Such oxides are more common on the right side of the periodic table, increasing in acidic nature from left to right across a period.Additionally, some oxides, known as amphoteric oxides, can exhibit both basic and acidic properties depending on the environment. Recognizing these oxide types helps in predicting how substances might react in different chemical settings.
