Question

Silicon is the fundamental component of integrated circuits. Si has the same structure as diamond. (a) Is Si a molecular, metallic, ionic, or covalent- network solid? (b) Silicon readily reacts to form silicon dioxide, ${\mathrm{SiO}}_2$, which is quite hard and is insoluble in water. Is ${\mathrm{SiO}}_2$ most likely a molecular, metallic, ionic, or covalent- network solid?

Short answer

Silicon is a covalent-network solid, and silicon dioxide (${\mathrm{SiO}}_2$) is most likely a covalent-network solid.

Step-by-step solution

Silicon has the same structure as diamond, which means it has a covalent-network structure. In this structure, each silicon atom is covalently bonded to four other silicon atoms, forming a three-dimensional network. #Step 2: Identifying the type of solid based on the structure#

Since silicon has a covalent-network structure, it is a covalent-network solid. Answer: Silicon is a covalent-network solid. #b) Determining the type of solid that silicon dioxide forms# #Step 1: Understanding the properties of Silicon dioxide#

Silicon dioxide (${\mathrm{SiO}}_2$) is quite hard and insoluble in water. This suggests it has a strong network of bonds holding the atoms together. #Step 2: Identifying the most likely type of solid based on the properties#

Since silicon dioxide (${\mathrm{SiO}}_2$) is quite hard and insoluble in water, it is most likely a network solid. Specifically, it forms a covalent-network solid, where each silicon atom is covalently bonded to four oxygen atoms, forming a three-dimensional network. Answer: Silicon dioxide (${\mathrm{SiO}}_2$) is most likely a covalent-network solid.

Key concepts

Exploring Silicon

Silicon is an essential element in the world of technology, especially known for its role in making integrated circuits and computer chips. This is largely due to its structure, which mirrors that of diamond. In this structure, each silicon atom is covalently bonded to four other silicon atoms. These bonds create a robust three-dimensional network and make silicon a covalent-network solid.

The unique properties of silicon come from this structure. Instead of being composed of small, discrete molecules, covalent-network solids form extensive grids that give them strength and stability. This is why materials like silicon are often very hard and have a high melting point. Let's delve deeper into how silicon's covalent bonds shape its characteristics.

Unwrapping Silicon Dioxide

Silicon dioxide, also known as SiO₂, is another fascinating compound that plays a critical role in the world around us. Found abundantly in nature as quartz, it is a primary component of sand. Much like silicon, silicon dioxide forms a covalent-network solid. However, its structure involves silicon atoms bonded to four oxygen atoms.

What makes silicon dioxide stand out is its incredible hardness and ability to resist being dissolved in water. These traits are symptomatic of its strong network of bonds. In a silicon dioxide lattice, each oxygen atom bridges two silicon atoms, forming a repeating structure that contributes to its durability and insolubility.

• Hardness: Silicon dioxide is famously tough, making it important in materials used for cutting or grinding.
• Insolubility: It does not dissolve in water, which makes it ideal for waterproof applications.

These properties are directly derived from its covalent-network structure, providing both strength and stability.

Solid State Chemistry Fundamentals

Solid state chemistry focuses on understanding the properties and behaviors of solids, which vary greatly depending on their structure. Covalent-network solids like silicon and silicon dioxide exemplify how structure determines function.

Understanding the intricacies of solid state chemistry helps us grasp why certain materials have specific properties. For instance, in covalent-network solids:

• Every atom is connected through covalent bonds in extensive three-dimensional frameworks.
• Such structures grant high melting points and significant hardness.

Exploring these concepts reveals why the materials we use are chosen for specific applications. From industrial machinery to everyday electronics, the principles of solid state chemistry provide the foundations that allow us to harness these materials effectively.