Question

Silicon is an important constituent of (a) sand (b) atmosphere (c) plants (d) water bodies.

Short answer

Silicon is an important constituent of (a) sand.

Step-by-step solution

Identifying the source of silicon

Silicon is a chemical element that is most commonly found in the Earth's crust. It is not a gas and is present in very minimal quantities in the atmosphere. Also, it is not primarily found in water bodies or in living organisms like plants in significant amounts.

Understanding where silicon is most abundant

Silicon is most abundant as a component of sand and other minerals, where it is combined with oxygen to form silica, or silicon dioxide (SiO2). This compound is the primary constituent of sand.

Key concepts

Chemical Elements

Chemical elements are the fundamental building blocks of matter, each distinguished by a unique atomic structure with a specific number of protons, known as the atomic number. These elements are organized in the periodic table based on their chemical properties. Silicon, for example, is the 14th element on the periodic table, identified by the symbol 'Si'. It stands out for its role in the semiconductor industry and is also a key ingredient in many materials found on Earth.
Understanding the behavior and interaction of chemical elements like silicon is vital for various scientific fields, including chemistry, physics, and material science. Silicon, being a metalloid, shares properties of both metals and non-metals, which makes it versatile in its applications. This adaptability can be seen in its presence in a range of forms, from pure crystalline silicon used in electronic devices to its compounds, like silicon dioxide, found in nature.

Silicon Dioxide

Silicon dioxide, also known as silica, is a chemical compound composed of one silicon atom and two oxygen atoms, with the molecular formula SiO2. This compound is most commonly recognized as quartz in its crystalline form, and it is found abundantly in sand, making it a significant component of the Earth's crust.
Silica is not only an essential constituent of sand but is also present in many rocks, such as granite and sandstone. It has a high melting point and is resistant to many chemical reactions, which means it provides stability to the structures it forms. In everyday life, we encounter silicon dioxide in various forms—glass, ceramics, and even in certain food products as an anti-caking agent. When discussing exercises related to silicon in educational materials, emphasizing the prevalence of silicon dioxide in sand can help students connect its significance to familiar, tangible substances.

Earth's Crust Composition

The Earth's crust is like a shell surrounding our planet, composed of a variety of elements and minerals. Silicon plays a crucial role as it is the second most abundant element in the Earth's crust, after oxygen. When it combines with oxygen, it forms silicates, which are the most common minerals making up over 90% of the Earth's crust.
Students often benefit from picturing the Earth’s crust as a giant jigsaw puzzle of tectonic plates made up of rocks and minerals. Within these plates, silicates such as silicon dioxide form structures ranging from the sands of our beaches to the awe-inspiring peaks of mountains. By focusing on the sheer abundance of silicon in the crust, learners can better appreciate its fundamental role in shaping our planet's surface and the reasoning behind why, in an exercise question, sand would be recognized as an important constituent containing silicon.