Question

Give the symbol for a metalloid in the third period and then identify a property of this element.

Short answer

The metalloid in the third period is silicon (Si), known for its semiconductor properties.

Step-by-step solution

Identify Metalloids

Metalloids are elements with properties intermediate between metals and non-metals. The elements commonly classified as metalloids include boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and polonium (Po).

Locate Period 3 Elements

Period 3 of the periodic table includes the elements from sodium (Na) to argon (Ar). These include sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and argon (Ar).

Match Metalloids and Period 3

From the list of metalloids, we identified silicon (Si) as being part of Period 3. Thus, the metalloid in the third period is silicon (Si).

Identify a Property of Silicon

Silicon (Si) is known for its semiconductor properties, making it useful in electronic devices. It can conduct electricity better than non-metals but not as well as pure metals, especially under certain conditions.

Key concepts

Periodic Table

The periodic table is a fundamental tool in chemistry that organizes all known elements in a systematic way. It arranges elements by increasing atomic number, which is the number of protons in the nucleus of an atom. This layout not only shows the atomic structure but also reveals patterns in element properties, such as reactivity and states of matter.

The table is organized into rows called periods and columns known as groups. Periods indicate elements with the same number of electron shells, with each subsequent period adding a shell. Groups, on the other hand, contain elements with similar chemical and physical properties, owing to their similar electron configurations. This resemblance comes from the elements having the same number of electrons in their outermost shell.

One of the unique features of the periodic table is that it includes different categories of elements like metals, non-metals, and metalloids. Metalloids, for instance, exhibit properties of both metals and non-metals, making them versatile for various applications.

Semiconductors

Semiconductors are materials with electrical conductivities that lie between conductors (like metals) and insulators (such as glass). Silicon is one of the most well-known semiconductors and is widely used in electronic devices. The unique property that defines a semiconductor is its ability to conduct electricity under certain conditions, such as changes in temperature or when impurities are added.

These materials have a unique electron structure, with a band gap between the valence and conduction bands. At absolute zero, pure semiconductors are insulators, but at room temperature, electrons can jump from the valence band to the conduction band, allowing electric current to flow.

Furthermore, semiconductors can be modified with impurity atoms to enhance their electrical properties, a process known as doping. Doping can create excess electrons, leading to n-type semiconductors, or it can create an absence of electrons (holes), resulting in p-type semiconductors. These characteristics make semiconductors integral to modern electronics, including integrated circuits and solar cells.

Element Properties

Elements possess various properties that define their chemical and physical behavior. These properties can be classified into two main types: chemical properties and physical properties.

Chemical properties describe how an element reacts with other substances, indicating its reactivity, potential to form compounds, and stability under different conditions. For example, some elements might readily bond with oxygen, forming oxides, while others remain largely unreactive.

Physical properties, on the other hand, are those that can be observed without changing the substance's chemical identity. These include attributes like state (solid, liquid, or gas), melting and boiling points, and density.

• Metalloids, like silicon, often display a mix of these properties from both metals and non-metals.
• They typically have intermediate electrical conductivity, making them ideal for semiconductor applications.
• They can also exist in various states and forms depending on environmental conditions.

Understanding these properties helps scientists and engineers select appropriate materials for specific applications, leveraging their unique characteristics.