Chemistry of Main Group Elements - Course Introduction (Detailed Notes)

1. Classification of Elements:

• Metals: Elements that readily lose electrons to form positive ions (cations).
  • Alkali metals (Group 1): Highly reactive, form 1+ ions.
  • Alkaline earth metals (Group 2): Less reactive than alkali metals, form 2+ ions.
• Non-metals: Elements that readily accept electrons to form negative ions (anions).
  • Halogens (Group 17): Highly reactive, form 1- ions.
  • Noble gases (Group 18): Unreactive, form stable monoatomic gases.
• Metalloids: Elements that have properties of both metals and non-metals.
  • Boron (Group 13), Silicon (Group 14), Germanium (Group 14), Arsenic (Group 15), Antimony (Group 15), Tellurium (Group 16).

2. Periodic Trends (Variations Across the periodic Table):

• Atomic size and radius: Atomic radius decreases across a period (left to right) and increases down a group (top to bottom).
• Ionization energy: Ionization energy increases across a period and decreases down a group.
• Electron affinity: Electron affinity increases across a period and decreases down a group.
• Electronegativity: Electronegativity increases across a period and decreases down a group.
• Oxidation states: Oxidation states of elements become more positive across a period and more negative down a group.

3. Structures and Bonding:

• Ionic bonding: Involves the transfer of electrons from a metal atom to a non-metal atom, resulting in the formation of positively charged cations and negatively charged anions.
• Covalent bonding: Involves the sharing of electron pairs between atoms, resulting in the formation of molecules.
• Metallic bonding: Involves the attraction between positively charged metal ions and the sea of mobile electrons in a metal lattice.

4. Nomenclature:

• Systematic naming of elements and compounds according to their composition and structure.
• IUPAC (International Union of Pure and Applied Chemistry) guidelines for naming inorganic compounds.

5. Chemical Reactions and Reactivity of Main Group Elements:

• Reactivity of alkali metals and alkaline earth metals: Highly reactive, readily react with water, oxygen, and halogens.
• Reactivity of halogens: Highly reactive, readily react with metals, non-metals, and organic compounds.
• Reactivity of noble gases: Unreactive under normal conditions.
• Formation and properties of oxides, hydroxides, carbonates, and sulfates: Reactions of main group elements with oxygen, water, and carbon dioxide.

6. Applications and Uses of Main Group Elements:

• Industrial applications: Catalysts, batteries, semiconductors, glass, cement, fertilizers.
• Everyday uses: Food preservation, cosmetics, pharmaceuticals, cleaning products, energy storage.

References:

• NCERT Chemistry, Class 11, Chapter 3: Classification of Elements and Periodicity in Properties
• NCERT Chemistry, Class 11, Chapter 4: Chemical Bonding and Molecular Structure
• NCERT Chemistry, Class 12, Chapter 1: The Solid State
• NCERT Chemistry, Class 12, Chapter 2: Solutions
• NCERT Chemistry, Class 12, Chapter 3: Electrochemistry
• NCERT Chemistry, Class 12, Chapter 10: The d- and f- Block Elements