Problem 41 - Chemistry: The Central Science in SI Units, Global Edition

Question

For each of the following elements, write its chemical symbol, 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, \((\mathbf{g})\) 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: (a) Radon

Radon is a noble gas found in the periodic table with the chemical symbol Rn. Look for Radon in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 2: Radon Information

Chemical Symbol: Rn Atomic Number: 86 Element Type: Nonmetal

Step 3: (b) Tellurium

Tellurium is a chemical element found in the periodic table with the chemical symbol Te. Look for Tellurium in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 4: Tellurium Information

Chemical Symbol: Te Atomic Number: 52 Element Type: Metalloid

Step 5: (c) Cadmium

Cadmium is a chemical element found in the periodic table with the chemical symbol Cd. Look for Cadmium in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 6: Cadmium Information

Chemical Symbol: Cd Atomic Number: 48 Element Type: Metal

Step 7: (d) Chromium

Chromium is a chemical element found in the periodic table with the chemical symbol Cr. Look for Chromium in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 8: Chromium Information

Chemical Symbol: Cr Atomic Number: 24 Element Type: Metal

Step 9: (e) Barium

Barium is a chemical element found in the periodic table with the chemical symbol Ba. Look for Barium in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 10: Barium Information

Chemical Symbol: Ba Atomic Number: 56 Element Type: Metal

Step 11: (f) Selenium

Selenium is a chemical element found in the periodic table with the chemical symbol Se. Look for Selenium in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 12: Selenium Information

Chemical Symbol: Se Atomic Number: 34 Element Type: Nonmetal

Step 13: (g) Sulphur

Sulphur is a chemical element found in the periodic table with the chemical symbol S. Look for Sulphur in the periodic table, find its atomic number and determine if it is a metal, metalloid, or nonmetal.

Step 14: Sulphur Information

Chemical Symbol: S Atomic Number: 16 Element Type: Nonmetal

Key Concepts

Chemical Symbols

Chemical symbols are one or two-letter abbreviations for the names of chemical elements. They are derived from the elements' English names or, sometimes, from their Latin or other traditional names. For instance, the chemical symbol for Hydrogen is 'H', which comes from its English name. Conversely, the symbol for Gold, 'Au', is based on its Latin name, 'Aurum'.

These symbols are universally used in the scientific community, making communication clearer and more efficient. Knowing the chemical symbols allows you to quickly identify the elements they represent on the periodic table.

Let's consider some of the elements from our exercise:

• Radon - Rn
• Tellurium - Te
• Cadmium - Cd
• Chromium - Cr
• Barium - Ba
• Selenium - Se
• Sulphur - S

Understanding chemical symbols aids not only in locating elements but also in shorthand notation for chemical reactions.

Atomic Number

The atomic number of an element is crucial as it defines the chemical element's identity. It represents the number of protons found in the nucleus of an atom of that element. The atomic number is always a whole number and displayed prominently above the chemical symbol in each cell of the periodic table.

Why is the atomic number important?

• Determines the element's position on the periodic table.
• Dictates the chemical behavior of an element.
• Identifies the number of electrons in a neutral atom.

For example, in the exercise:

• Radon has an atomic number of 86.
• Tellurium's atomic number is 52.
• Cadmium's atomic number is 48.

Grasp the atomic number to understand the foundational structure of any element, paving the way for easier comprehension of its properties and interactions.

Metallic Classification

The classification of elements as metals, metalloids, or nonmetals is based on their physical and chemical properties. This classification helps predict behavior in various reactions and is crucial in material science.

Metals, like Barium (Ba) and Cadmium (Cd), are generally solid (with the exception of mercury), shiny, good conductors of heat and electricity, malleable, and ductile. Nonmetals, such as Sulphur (S) and Selenium (Se), are more diverse in their properties. They can be gases, liquids, or solids, and are typically poor conductors of heat and electricity. They often gain electrons during reactions.

Metalloids, like Tellurium (Te), possess properties intermediate between metals and nonmetals. They can conduct electricity better than nonmetals but not as well as metals, making them useful in semiconductor technology.

Understand these classifications to predict the elements' behavior and their usage in practical applications.

Noble Gases

Noble gases are a group of elements in the far right column of the periodic table, known for their lack of reactivity under standard conditions due to a full set of valence electrons. These elements include Helium, Neon, Argon, Krypton, Xenon, and Radon.

What traits distinguish noble gases?

• Colorless, tasteless, and odorless.
• Nonflammable and typically exist in gaseous state at room temperature.
• Have complete valence electron shells, making them generally inert.

Radon (Rn), part of our exercise, is a noble gas with an atomic number of 86. Despite being radioactively significant, it follows the noble gas trait of low reactivity. Understanding noble gases helps us comprehend inert behavior in chemical reactions and their applications in fields like lighting and refrigeration.