Lecture: The Periodic Table and its Organization

Overview

• Objectives:
  • Understand the organization of the periodic table.
  • Identify different types of elements (metals, metalloids, non-metals).
  • Explain the shape and structure of the periodic table.
  • Describe the significance of periods and groups.
  • Recognize the common names and properties of specific groups.

Main Categories of Elements

• Metals:

  • Largest category, shaded in blue on the periodic table.
  • Located in the middle and left-hand part of the periodic table.
  • Properties:
    • Physical: Solids at room temp, shiny, malleable (thin sheets), ductile (thin wires), good conductors of heat and electricity.
    • Chemical: Tend to lose electrons to form positive ions.

• Non-Metals:

  • Shaded in green, located in the upper right-hand part of the periodic table.
  • Properties:
    • Physical: Solids, liquids, gases at room temp, dull appearance, not easily workable, poor conductors of heat and electricity.
    • Chemical: Tend to gain electrons to form negative ions.

• Metalloids:

  • Shaded in orange, located between metals and non-metals.
  • Properties: Show characteristics of both metals and non-metals, semi-conductors, variability in appearance, variable ionic charges.

Organization by Periods and Groups

• Periods:

  • Horizontal rows on the periodic table (Period 1, Period 2, etc.).

• Groups (or Families):

  • Vertical columns on the periodic table.
  • Two numbering systems: Modern (1-18) and Older (1A, 2A, B's, etc.).
  • We use the older system for useful, quick-access information.
  • Which A or B classification to use?: Older classification (A’s and B’s) provides direct useful information.

Importance of Groups

• Elements in the same group have similar chemical properties due to similar valence electron configurations.
• Group Common Names and Properties:
  • Group 1A (Alkali Metals): Form +1 ions.
  • Group 2A (Alkaline Earth Metals): Form +2 ions.
  • Transition Metals: Form various positive ions.
  • Group 3A: Usually form +3 ions.
  • Group 4A: Typically no ions formed.
  • Group 5A: Form -3 ions.
  • Group 6A: Form -2 ions.
  • Group 7A (Halogens): Form -1 ions.
  • Group 8A (Noble Gases): Do not form ions.

Summary

• Shape of the Table: Organized by groups with similar chemical properties causing the table to have its unique shape.
• Review:
  • Periods = Horizontal rows.
  • Groups = Vertical columns.
  • Common names and properties of element groups critical for understanding chemical behavior.
  • Upcoming use of these ion formation properties in future topics.