Problem 11 - Chemistry The Central Science

Question

Identify each of the following elements as a metal, nonmetal, or metalloid: (a) phosphorus, (b) strontium, (c) manganese, (d) selenium, (e) sodium, (f) krypton.

Step-by-Step Solution

Answer

(a) Phosphorus is a nonmetal. (b) Strontium is a metal. (c) Manganese is a metal. (d) Selenium is a nonmetal. (e) Sodium is a metal. (f) Krypton is a nonmetal.

Step 1: (a) Phosphorus

Phosphorus has the symbol "P" and is found in group 15 of the periodic table. Elements in this group are nonmetals. Therefore, phosphorus is a nonmetal.

Step 2: (b) Strontium

Strontium has the symbol "Sr" and is found in group 2 of the periodic table. Elements in this group are known as alkaline earth metals. Therefore, strontium is a metal.

Step 3: (c) Manganese

Manganese has the symbol "Mn" and is found in group 7 as a transition metal in the periodic table. Transition metals are classified as metals due to their metallic properties. Therefore, manganese is a metal.

Step 4: (d) Selenium

Selenium has the symbol "Se" and is found in group 16 of the periodic table. Elements in this group are commonly classified as nonmetals. Therefore, selenium is a nonmetal.

Step 5: (e) Sodium

Sodium has the symbol "Na" and is found in group 1 of the periodic table. Elements in this group are known as alkali metals. Therefore, sodium is a metal.

Step 6: (f) Krypton

Krypton has the symbol "Kr" and is found in group 18 of the periodic table. Elements in this group are known as noble gases which are nonmetals. Therefore, krypton is a nonmetal.

Key Concepts

Metals

Metals are fascinating elements widely known for their characteristic shiny appearance and excellent conductive abilities. They are generally found on the left side and towards the bottom of the periodic table. Here are some key properties of metals that help us to easily identify them:

• **Conductivity**: Metals are excellent conductors of electricity and heat, which makes them crucial for electronic and thermal applications.
• **Malleability and Ductility**: They can be hammered into thin sheets (malleable) or drawn into wires (ductile), making them very useful in manufacturing and construction.
• **Luster**: Metals often have a shiny or metallic luster, a property that contributes to their visual appeal in jewelry and decorations.
• **High Melting Points**: Most metals have high melting points, maintaining their solid form at high temperatures.

Common examples of metals include **sodium (Na)**, **strontium (Sr)**, and **manganese (Mn)**. These elements belong to groups like alkali metals, alkaline earth metals, and transition metals, each having their own unique uses and properties.

Nonmetals

Nonmetals are situated primarily on the right side of the periodic table. Unlike metals, these elements usually do not have a shiny appearance and possess properties opposite to metals. Let's explore what makes nonmetals distinct:

• **Poor Conductors**: Nonmetals are poor conductors of heat and electricity. Hence, they are often used as insulators.
• **Brittle**: Nonmetals are typically brittle if solid, meaning they can break or shatter easily rather than bending.
• **Variety of States**: Nonmetals can exist in all three states of matter at room temperature: gases (like oxygen and krypton), solids (such as phosphorus and selenium), and one liquid (bromine).
• **Dull Appearance**: They usually appear dull and lack the luster commonly associated with metals.

Elements like **phosphorus (P)**, **selenium (Se)**, and **krypton (Kr)** are examples of nonmetals, which play vital roles across biological processes, industrial applications, and more.

Metalloids

Metalloids represent a fascinating group of elements that possess properties of both metals and nonmetals. These elements are typically found along the zig-zag line on the periodic table, separating metals and nonmetals. Here’s what you should know about metalloids:

• **Semiconductors**: Metalloids can conduct electricity better than nonmetals but not as well as metals. This makes them excellent materials for semiconductors in the electronics industry.
• **Varied Appearance**: They can appear metallic but are generally more brittle than metals.
• **Intermediate Properties**: Since they share traits of both metals and nonmetals, they can bond and interact in versatile ways, making them crucial in materials science.

Common metalloids include silicon (Si) and germanium (Ge), which are crucial in making computer chips and other electronic devices.

Element Classification

Classifying elements is an essential process for understanding their properties and potential uses. The classification primarily includes three main categories based on their attributes: **metals**, **nonmetals**, and **metalloids**. Each category is defined by a set of properties and its position on the periodic table.

• **Metals** are typically positioned on the left side and lower middle of the periodic table.
• **Nonmetals** are usually found on the right side, including gases like krypton and solids like phosphorus.
• **Metalloids** are located along the diagonal zone between metals and nonmetals, displaying characteristics of both.

Understanding these classifications helps scientists and engineers select appropriate materials for various applications based on the elements' innate characteristics. This foundational knowledge also guides further exploration and application in fields like chemistry, physics, and materials science.