In-Depth Notes on States of Matter and the Periodic Table

States of Matter

• Matter exists in three primary states:
  • Solids
  • Liquids
  • Gases

The Periodic Table of Elements

Key Concepts

• Elements are substances consisting of only one type of atom.
• The Periodic Table organizes these elements based on their properties and atomic structure.
• Categories of Elements:
  • Metals: Good conductors of heat and electricity; typically solid at room temperature.
  • Nonmetals: Poor conductors, can be gases or solids; diverse chemical properties.
  • Metalloids: Elements that have properties of both metals and nonmetals.

Properties of Categories

• Metals: Shiny, malleable, ductile, conduct heat and electricity well.
• Nonmetals: Varied states (gases, liquids, solids); often brittle and dull.
• Metalloids: Intermediate properties; useful in semiconductors.

Periodic Table Groups/Families

• The table is organized into groups/families based on similar properties.
  • Alkali Metals:
  • Located in Group 1; highly reactive; have 1 valence electron.
  • Alkaline Earth Metals:
  • Group 2; reactive, but less so than alkali metals; have 2 valence electrons.
  • Transition Metals:
  • Found in the center of the table; known for complex electron configurations.
  • Other Metals:
  • Include elements such as aluminum and tin; have metallic properties but are not found in the transition series.
  • Metalloids:
  • Elements such as silicon and germanium that exhibit properties of both metals and nonmetals.
  • Nonmetals:
  • Include gases like nitrogen and oxygen, and solids like carbon and sulfur.
  • Halogens:
  • Group 17 elements; highly reactive nonmetals.
  • Noble Gases:
  • Group 18; inert and nonreactive gases due to their full valence shell.

Valence Electrons

• Valence Electrons are electrons in the outer shell of an atom that determine its chemical properties.
• The number of valence electrons informs the reactivity and bonding of the element.
  • Higher energy levels indicate more reactive elements, particularly in groups 1 and 2 (alkali and alkaline earth metals).
  • Noble gases possess a complete set of valence electrons (8), making them largely unreactive.