Lecture on Electron Configuration

Overview

• This lecture is aimed at understanding electron configuration, which will help reduce stress in learning.
• Focus on orbitals, sublevels, and electron placement.

Atomic Orbitals

• Definition: Probability of finding an electron in a point in space, where electrons are likely to be.
• Types:
  • s Sublevel: Sphere-shaped, contains 1 orbital, holds 2 electrons.
  • p Sublevel: Contains 3 orbitals, holds 6 electrons.
  • d Sublevel: Contains 5 orbitals, holds 10 electrons.
  • f Sublevel: Contains 7 orbitals, holds 14 electrons.

Orbital Filling Order

• Electrons fill lower energy orbitals first (e.g., 1s, then 2s, etc.).
• Determined by the coefficient in front (1 is lower than 2).
• Use periodic table position to determine order, not memorization.

Periodic Table Organization

• s Sublevel: First two groups, including helium.
• p Sublevel: Next four groups (purple area).
• d Sublevel: Transition metals, one less than row number (n-1).
• f Sublevel: Lanthanides and actinides, two less than row number (n-2).

Electron Configuration Notation

• Superscript indicates number of electrons in orbital.
• Orbital type indicates shape (s, p, d, f).
• Coefficient indicates energy level.

Full Electron Configuration

• Example: Carbon
  • 1s² 2s² 2p²
• Match with periodic table position.

Condensed Electron Configuration

• Uses the noble gas from the previous row as a reference point.
• Example: Phosphorus
  • Full: 1s² 2s² 2p⁶ 3s² 3p³
  • Condensed: [Ne] 3s² 3p³

D and F Sublevel Specifics

• d Sublevel: Energy level is one less than the row number (e.g., 4d becomes 3d).
• f Sublevel: Energy level is two less than the row number (e.g., 6f becomes 4f).
• Important to note breaks on the periodic table between blocks.

Practice Examples

• Iron (Fe)
  • Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
  • Condensed: [Ar] 4s² 3d⁶
• Mercury (Hg)
  • Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰
  • Condensed: [Xe] 6s² 4f¹⁴ 5d¹⁰

Tips for Studying

• Focus on understanding periodic table layout and electron filling.
• Use condensed configuration for simplification.
• Practice various elements for familiarity.

By understanding the structure and logic of electron configurations, students can effectively navigate and apply this knowledge without relying on rote memorization. The key lies in using the periodic table as a guide for systematic electron filling.