Lecture Notes on Periodic Table and Related Concepts

Introduction and Greetings

• The lecturer greeted the audience and engaged in brief small talk.
• Mentioned starting the topic of Periodic Table under Inorganic Chemistry.

Introduction to the Periodic Table

• Importance of the periodic table in understanding Inorganic Chemistry.
• Elements are organized based on increasing atomic number.
• Structure includes periods (horizontal rows) and groups (vertical columns).
• Divided into blocks: s, p, d, f blocks.

Structure and Layout

Blocks of Periodic Table

• s-block: Groups 1-2 (except Helium).
• p-block: Groups 13-18.
• d-block: Transition elements, Groups 3-12.
• f-block: Lanthanides and Actinides, placed separately at the bottom.

Periodic Trends

• Atomic size: Decreases across a period, increases down a group.
• Ionization energy: Energy required to remove an electron, increases across a period, decreases down a group.
• Electron affinity: Energy change when an electron is added to a neutral atom, generally becomes more negative across a period.
• Electronegativity: Tendency of an atom to attract electrons in a bond, increases across a period, decreases down a group.

Specific Group and Period Discussions

Group 1: Alkali Metals

• Highly reactive, especially with water.
• Low ionization energies.

Group 2: Alkaline Earth Metals

• Less reactive than alkali metals.
• Higher densities and melting points.

Transition Metals (d-block)

• Conductive, malleable, and ductile.
• Form colored compounds.
• Variable oxidation states.
• Examples: Fe, Cu, Zn.

Lanthanides and Actinides (f-block)

• Lanthanides: Rare earth elements, high magnetic susceptibility.
• Actinides: Radioactive, used in nuclear applications.

Special Topics

Effective Nuclear Charge (Zeff)

• The net positive charge experienced by valence electrons.
• Formula: Zeff = Z - S (where Z is atomic number, S is screening constant).
• Increases across a period.

Shielding Effect

• Inner electrons shield outer electrons from the full charge of the nucleus.
• Shielding effect increases down a group.

Practical Applications

Identifying Elements

• Using atomic number to find the position in the periodic table.
• Determining the group and period by electron configuration.

Chemical Properties and Trends

• Reactivity trends in metals and non-metals.
• Predicting ion formation and oxidation states.

Key Takeaways

• The periodic table is a fundamental tool in chemistry for predicting elemental behavior and properties.
• Understanding periodic trends is crucial for mastering inorganic chemistry.
• Elements exhibit trends based on their position in the table, affecting their physical and chemical properties.

Conclusion

• Recap of the periodic table’s structure and trends.
• Encouragement to review the notes and understand the trends and their applications.
• End of the lecture with best wishes for studying.

📝 Thank You! Always keep revising and stay curious!