Question

Which nonradioactive elements are semimetals because their appearance resembles that of metals?

Short answer

The nonradioactive semimetals that resemble metals are boron, silicon, germanium, arsenic, antimony, and tellurium.

Step-by-step solution

Understanding Metals and Nonmetals

First, we need to understand the general characteristics of metals and nonmetals. Metals are generally shiny, good conductors of heat and electricity, and are malleable and ductile. Nonmetals, on the other hand, are not shiny and are poor conductors.

Identifying Semimetals

Semimetals, or metalloids, have properties that are intermediate between metals and nonmetals. They often have a metallic appearance like metals but do not possess all the other metallic characteristics.

Locating Semimetals on the Periodic Table

Semimetals can be found along the 'stair-step' line that distinguishes metals from nonmetals on the periodic table. These elements include boron, silicon, germanium, arsenic, antimony, and tellurium.

Determining Nonradioactive Semimetals

Among the semimetals, we need to exclude any that are radioactive. For the semimetals listed, none are primarily known as radioactive, making all of them applicable to this problem.

Key concepts

Nonradioactive Elements

Nonradioactive elements are those that do not undergo radioactive decay under normal conditions. In the periodic table, most elements are nonradioactive which means they are stable and do not emit radiation spontaneously. For students and researchers, understanding which elements aren't radioactive is crucial, especially when dealing with experiments where safety and environmental concerns are involved.

When considering semimetals in particular, which strike a balance between the properties of metals and nonmetals, identifying nonradioactive ones is straightforward since most commonly known semimetals do not exhibit radioactivity.

For instance:

• Boron (B)
• Silicon (Si)
• Germanium (Ge)
• Arsenic (As)
• Antimony (Sb)
• Tellurium (Te)

These elements do not naturally emit radiation and thus fit the definition of nonradioactive semimetals. Understanding this concept helps in areas like electronics and materials science, where the properties of semimetals are highly valued.

Periodic Table

The periodic table is a systematic arrangement of elements, where they are placed in order of their atomic number, electron configurations, and recurring chemical properties. Invented by Dmitri Mendeleev, it serves as a map for chemists and researchers to understand the relationships between different elements and predict how they might react.

The periodic table is structured in rows and columns:

• **Rows** are called periods, and each period corresponds to a shell of electron orbitals being filled.
• **Columns** are known as groups, and elements within the same group share similar chemical properties due to having the same number of electrons in their outer shell.

Semimetals are found along a stair-step line on the periodic table dividing metals from nonmetals, establishing a visual and practical method for identifying these unique elements. This special location is crucial because it highlights elements that are neither fully metallic nor nonmetallic.

Metals and Nonmetals

Elements in the periodic table are broadly categorized into metals, nonmetals, and metalloids (semimetals). Metals occupy most of the table and are known for their lustrous appearance, ability to conduct heat and electricity, and malleability. Nonmetals, contrastingly, tend to be dull, poor conductors, and are often brittle when solid.

Here’s a simple way to differentiate:

• **Metals:** Shiny, conductive, malleable, ductile.
• **Nonmetals:** Not shiny, poor conductors, not malleable.

Semimetals possess a combination of metallic and nonmetallic properties, making them unique in their appearance and functionality. For example, they might appear shiny like metals but be poor conductors like nonmetals. This diversity is what makes semimetals essential in various technological applications, like semiconductors in electronics.

Understanding these differences is key in fields ranging from chemistry to engineering, where the choice of material depends on the desired properties of a product or experiment.