Chapter 1: The Light Elements

• Periodic Table Structure

  • Organized by recurring properties of elements.

  • Arranged in periods (rows) and groups (columns).

• Periods

  • Elements in the same period share the same number of energy shells.

  • Each new period represents an additional energy shell.

    • Example:

      • Hydrogen (1st period) has 1 shell.

      • Potassium (4th period) has 4 shells.

• Groups

  • Elements in the same group have the same number of valence electrons (outermost shell electrons).

  • Valence electrons determine chemical reactivity.

Chapter 2: Period To Period

• Reactivity and Bond Formation

  • The number of valence electrons influences an element's reactivity.

  • Elements in the same group exhibit similar chemical properties due to having the same number of outer shell electrons.

• Group Characteristics

  • Group number indicates the number of valence electrons.

    • Example: Group 7 elements (Fluorine, Chlorine, Iodine, Bromine, Astatine) all have 7 valence electrons.

• Gradual Change in Properties

  • Properties of elements show gradual changes as you move down a group.

    • Example: Chlorine (Group 7, Period 3) has 3 energy levels and 7 valence electrons, while other group members have their outer electrons in different