Lecture 5.4: The Periodic Table

Introduction

• Focus on understanding the periodic table in detail.
• Historical context: First periodic table by Mendeleev in 1872.
• Grouping of elements similar to today’s periodic table.

Periodic Table Overview

• Lists all known elements, including man-made elements.
• Man-made elements created by nuclear reactions, not naturally occurring.

Information on the Periodic Table

• Element symbol, atomic mass, atomic number.
• State of matter: Solid, liquid, or gas.
  • Most elements are solids.
  • Gases: Noble gases, nitrogen, oxygen, chlorine, hydrogen.
  • Liquids: Bromine and mercury.

Structure of the Periodic Table

• Rows (Periods): Horizontal lines.
• Columns (Groups): Vertical lines.

Groups in the Periodic Table

• Group 1: Alkali Metals
  • Soft metals, highly reactive with water.
  • Example: Reaction with water is exothermic (releases heat).
• Group 2: Alkaline Earth Metals
  • Reactive with water, form hydroxide bases.
  • Softer with lower density than other metals.
• Groups 3-12: Transition Metals
  • Traditional hard, dense metals (e.g. copper, iron).
  • Do not react violently with water.
  • Produce colored solutions in water.
• Metalloids
  • Properties of both metals and non-metals.
  • Act as semiconductors and are temperature sensitive.
• Group 15: Nictogens
  • Named for nitrogen; associated with suppressing fire.
  • Based on electron configuration.
• Group 16: Chalcogens
  • Includes oxygen and sulfur; found in ores.
• Group 17: Halogens
  • Diatomic, form salts.
• Group 18: Noble Gases
  • Inert, odorless, colorless.

Special Rows: Lanthanides and Actinides

• Rare earth elements, often radioactive.

Key Concepts

• Recognize and name groups and elements in the periodic table.
• Differentiate between metals, non-metals, and metalloids.
• Essential to understand for determining compound types (ionic vs. covalent).

Memorization Requirement

• Know first 56 elements, their names, and symbols (not atomic mass).
• Importance of correct spelling.

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These notes summarize the key aspects of the periodic table as discussed in the lecture, focusing on the historical context, structure, and significance of different groups and elements within the table.