Problem 43 - Chemistry The Central Science In Si Units

Question

For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) polonium, (b) strontium, (c) neon, (d) rubidium, (e) bromine.

Step-by-Step Solution

Answer

Po is a metalloid in the Chalcogens; Sr is a metal in the Alkaline Earth Metals; Ne is a nonmetal in the Noble Gases; Rb is a metal in the Alkali Metals; Br is a nonmetal in the Halogens.

Step 1: Identify the Chemical Symbol

Begin by identifying the chemical symbol for each element listed in the exercise. - Polonium: Po - Strontium: Sr - Neon: Ne - Rubidium: Rb - Bromine: Br

Step 2: Determine the Group Name

Using the periodic table, find the group or family name for each element: - Po (Polonium) is part of the Chalcogens group. - Sr (Strontium) is part of the Alkaline Earth Metals. - Ne (Neon) is part of the Noble Gases. - Rb (Rubidium) is part of the Alkali Metals. - Br (Bromine) is part of the Halogens.

Step 3: Classify the Element Type

Finally, determine whether each element is a metal, metalloid, or nonmetal: - Po (Polonium) is classified as a metalloid. - Sr (Strontium) is classified as a metal. - Ne (Neon) is classified as a nonmetal. - Rb (Rubidium) is classified as a metal. - Br (Bromine) is classified as a nonmetal.

Key Concepts

Chemical Elements

Chemical elements are the basic building blocks of everything around us. Each element is a pure substance made entirely of one type of atom. Because elements are distinct, they cannot be broken down into simpler substances by chemical means.

There are currently 118 recognized elements, each with its own unique characteristics. Students can identify an element by its atomic number, which represents the number of protons in the nucleus of its atoms. Some elements are very common and well-known, like hydrogen and oxygen, while others are rare and found in specialized applications.

Recognizing chemical elements is crucial in understanding chemical reactions and the composition of matter. By learning about different elements, students can gain insight into the natural world and the materials that make it up.

Element Classification

The periodic table organizes elements based on certain criteria, making it easier to study and understand them. Elements are classified by their properties into metals, nonmetals, and metalloids.

- **Metals:** These are elements that are typically hard, shiny, and conduct electricity and heat well. They often form positive ions by losing electrons. Examples include copper and gold. Metals are usually malleable and ductile, meaning they can be shaped or drawn into wires without breaking. - **Nonmetals:** These elements are generally poor conductors of heat and electricity. They usually have more varied appearances and states, including gases like neon or liquids like bromine. Nonmetals tend to gain electrons in chemical reactions, usually forming negative ions. - **Metalloids:** Metalloids have properties intermediate between metals and nonmetals. They are semiconductors, meaning they can conduct electricity but not as well as metals. Silicon is a common example of a metalloid used in electronics.

Understanding these classifications helps clarify how elements interact during chemical reactions.

Chemical Symbols

Chemical symbols are shorthand representations used to refer to chemical elements. Each chemical symbol is made up of one or two letters, the first being capitalized, and they are used universally to communicate about elements efficiently.

- **Single Letter Symbols:** Some elements have symbols that are represented by a single letter. For example, hydrogen's symbol is H, while potassium is represented as K. - **Two Letter Symbols:** Many elements use two letters to distinguish them from others, especially when multiple elements start with the same letter. For example, calcium has the symbol Ca, and carbon has the symbol C. In these cases, the first letter is uppercase and the second letter is lowercase. - **Historical and Language Origins:** The symbols may not always match the English names of elements. Some symbols are derived from Latin or other languages. For instance, the symbol for gold is Au, coming from the Latin word "aurum," and iron’s symbol is Fe, from the Latin "ferrum."

Mastering chemical symbols is fundamental for effective communication in science, allowing students to easily write formulas and equations.