Problem 15 - Chemistry and Chemical Reactivity

Question

Place the following oxides in order of increasing basicity: \(\mathrm{CO}_{2}, \mathrm{SiO}_{2}, \mathrm{SnO}_{2}\)

Step-by-Step Solution

Answer

Order of increasing basicity: CO₂, SiO₂, SnO₂.

Step 1: Understanding Basicity of Oxides

Basicity in oxides depends on the position of the element in the periodic table. Generally, moving from left to right across a period, oxides tend to be less basic or more acidic.

Step 2: Identify Group and Period of Elements

Determine the position of carbon (C), silicon (Si), and tin (Sn) in the periodic table. Carbon and silicon are both in Group 14, but carbon is in period 2, silicon in period 3, and tin in period 5.

Step 3: Compare Basicity Within the Group

In Group 14, basicity increases as you move down the group from non-metal oxides to metal oxides. Therefore, the order from least basic to most basic is CO₂ < SiO₂ < SnO₂.

Key Concepts

Periodic Table Trends

The periodic table is organized in a way that reveals various trends related to element properties. As you move across a period from left to right, elements change from metallic to non-metallic. This affects the basicity of their oxides. Metal oxides tend to be more basic, while non-metal oxides are more acidic. For instance, the oxides of elements on the left are more basic compared to those on the right. Moving down a group, elements become more metallic, increasing the basicity of their oxides. Understanding these trends is crucial when predicting chemical behavior.

Group 14 Elements

Group 14 of the periodic table includes elements like carbon (C), silicon (Si), and tin (Sn). These elements show a progression from non-metals to metals within the group. Carbon, at the top, is a non-metal, while tin, near the bottom, is a metal. This change influences the type of oxide they form:

• Carbon (CO₂): Forms acidic oxide.
• Silicon (SiO₂): Slightly acidic oxide.
• Tin (SnO₂): Basic oxide.

Thus, understanding the nature of Group 14 helps predict the basicity of its oxides.

Metal and Non-Metal Oxides

Oxides can be broadly classified into metal and non-metal oxides with distinct properties. Metal oxides, typically found on the left and towards the bottom of the periodic table, are basic.
Non-metal oxides, found on the right, are acidic. For example:

• CO₂: A non-metal oxide that is acidic.
• SiO₂: Exhibits characteristics of non-metal oxides, slightly acidic.
• SnO₂: Shows properties of metal oxides, more basic.

Recognizing these properties helps in understanding their reactivity and applications.

Chemical Periodicity

Chemical periodicity refers to the recurring trends that are observed in elements as we move through the periodic table. This periodicity arises due to the repeating nature of electron configurations.
For oxides:

• Across a period, the acidic nature increases due to an increase in non-metallic character.
• Down a group, basicity increases because of a rise in metallic character.

By studying these trends, chemists can predict the behavior of elements and their compounds, like the basicity of CO₂, SiO₂, and SnO₂.