Periodic Table Lecture Notes

Introduction

• Main Idea: Elements in a vertical column have similar chemical and physical properties.
• Structure: Arranged by increasing atomic number, which corresponds to the number of protons.
• Key Features:
  • Atomic Number: Whole number above the element symbol.
  • Elemental Symbol: First letter capitalized, second letter lowercase.
  • Atomic Weight: Weighted average of the element.

Development of the Periodic Table

• Mendeleev's Contribution:
  • Forefather of the periodic table.
  • Organized elements by increasing atomic mass and left spaces for undiscovered elements.
  • Recognized patterns in properties.
• Historical Discovery:
  • Color-coded development timeline of elements discovery (pre-1800 to post-1950s).

Element Groups

• Main Groups to Know:
  • Alkali Metals (Group 1): Highly reactive, form +1 cations.
  • Alkaline Earth Metals (Group 2): Less reactive than alkali, form +2 cations.
  • Halogens (Group 17): Very reactive non-metals.
  • Noble Gases (Group 18): Inert, non-reactive.
  • Transition Metals (Groups 3-12): Variable oxidation states.

Periodic Table Layout

• Stair Step Line: Separates metals from non-metals.
• Metalloids: Elements along the stair step, exhibit properties of both metals and non-metals.
• Inner Transition Metals: Lanthanides and Actinides (pulled out for space).
• Main Group Elements: Groups 1-2, 13-18.

Properties of Elements

• Metals:
  • Solid at room temperature, except mercury.
  • Shiny, conduct heat and electricity, malleable, ductile.
  • Lose electrons to form cations.
• Non-Metals:
  • Found in all states (solid, liquid, gas); e.g., sulfur, bromine, chlorine.
  • Poor conductors, brittle, gain electrons to form anions.
• Metalloids/Semiconductors:
  • Exhibit properties of both metals and non-metals.
  • Important for technology like semiconductors.

Important Concepts

• Groups vs. Periods:
  • Groups: Vertical columns (previously known as families).
  • Periods: Horizontal rows.
• Numbering Systems:
  • IUPAC: New system, 1-18.
  • Old System: Roman numerals for groups, letters for transition metals.

Recommendations

• Write notes directly on your periodic table for better retention.
• Familiarize with terms such as metals, non-metals, metalloids, and their properties.

Study Tips

• Use diagrams and color coding to understand different areas and elements on the periodic table.
• Relate properties and behaviors of elements to their positions on the table for easier memorization.