Lecture Notes on Periodic Table and Properties of Metals and Non-Metals

Overview of the Periodic Table

• Most elements are metals, located towards the bottom left of the table.
• Metals form positive ions (cations) like calcium (Ca²⁺).
• Non-metals either form negative ions (anions) like chloride (Cl⁻) or do not form ions.

Electron Arrangements and Ion Formation

• Stability is achieved when atoms have a full outer electron shell.
• Metals:
  • Located on the left side of the table.
  • Have few electrons in their outer shell.
  • Example: Calcium (group 2) has two electrons in its outer shell, easily loses them to form Ca²⁺.
• Non-Metals:
  • Example: Chlorine has seven outer electrons, requires a lot of energy to lose all and form a positive ion, hence forms Cl⁻ instead.

Reactivity of Metals

• Metals become more reactive towards the bottom of the table.
• Elements with more electron shells have outer electrons far from the nucleus.
  • Example: Lead (Pb) has six shells, making outer electrons less strongly held and more easily lost.

Physical Properties of Metals

• Metallic Bonding: Strong bonds unique to metals.
• Properties:
  • Malleable: Can be shaped without breaking.
  • Conductors of heat and electricity.
  • High melting and boiling points.
  • Shiny and sonorous (ringing sound when struck).

Properties of Non-Metals

• Tend to be dull in color and brittle.
• Low melting and boiling points; many are gases at room temperature.
• Poor conductors of electricity.
• Lower densities than metals.

Transition Metals

• Located in the center of the periodic table.
• Exhibit typical metallic properties.
• Additional Features:
  • Can form multiple ions (e.g., Chromium: Cr²⁺, Cr³⁺, Cr⁶⁺).
  • Transition metal ions are often colored (e.g., blue, green, orange).
  • Excellent catalysts: Increase the rate of chemical reactions without being consumed.
    • Examples: Iron in the Haber process for ammonia production, Nickel in hydrogenation of alkenes for margarine.

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End of Lecture