Problem 41 - Chemistry The Central Science In Si Units

Question

For each of the following elements, write its chemical sym. bol, locate it in the periodic table, give its atomic number and indicate whether it is a metal, metalloid, or nonmetal (a) radon, (b) tellurium, (c) cadmium, (d) chromium (e) barium, (f) selenium, (g) sulphur.

Step-by-Step Solution

Answer

(a) Radon: Rn, Atomic Number 86, Nonmetal; (b) Tellurium: Te, Atomic Number 52, Metalloid; (c) Cadmium: Cd, Atomic Number 48, Metal; (d) Chromium: Cr, Atomic Number 24, Metal; (e) Barium: Ba, Atomic Number 56, Metal; (f) Selenium: Se, Atomic Number 34, Nonmetal; (g) Sulphur: S, Atomic Number 16, Nonmetal.

Step 1: Identify the Element

Find the chemical symbol for each element. For example, radon is represented by "Rn".

Step 2: Locate on the Periodic Table

Determine where each element is located on the periodic table. Radon (Rn), for instance, is in Group 18, Period 6.

Step 3: Find the Atomic Number

Each element has a unique atomic number which indicates the number of protons in its nucleus. Radon, for example, has an atomic number of 86.

Step 4: Classify the Element

Determine if each element is a metal, nonmetal, or metalloid. Radon is considered a nonmetal due to its gaseous state and placement in Group 18.

Key Concepts

Chemical Symbols

Chemical symbols are a shorthand method to represent elements in the periodic table. Each chemical symbol usually consists of one or two letters, with the first letter always capitalized and the second letter always lowercase. These symbols are derived from either the current English name or the Latin name of the element.
For example:

• Radon is represented by "Rn"
• Tellurium by "Te"
• Cadmium by "Cd"

Learning chemical symbols is essential as it forms the foundation for writing chemical formulas and equations. Familiarity with these symbols will help you easily identify elements when viewing a periodic table or working on chemical reactions.

Element Classification

The periodic table groups elements into three main categories: metals, nonmetals, and metalloids. These classifications help predict the physical and chemical properties of an element based on its position in the periodic table.
Metals are typically shiny, conductive, and malleable.

• Cadmium ("Cd") and Barium ("Ba") are metals.

Nonmetals, in contrast, are often brittle in solid form and are poor conductors.

• Radon ("Rn") and Sulfur ("S") are nonmetals.

Metalloids have properties intermediate between metals and nonmetals.

• Tellurium ("Te") and Selenium ("Se") fall into this category.

Understanding these classifications will help you anticipate how an element might interact in chemical reactions or behave in different conditions.

Atomic Number

The atomic number is a fundamental property of an element. It tells us the number of protons found in the nucleus of an atom. Each element has a unique atomic number, and it is this number that defines the element.
For instance:

• Radon has an atomic number of 86.
• Sulfur has an atomic number of 16.
• Chromium ("Cr") has an atomic number of 24.

The atomic number not only indicates the number of protons but also, for neutral atoms, equals the number of electrons. This balance of protons and electrons determines many chemical properties and behaviors of the element.