Electron Configuration

Electron Configuration

Electron configuration is the arrangement of electrons in an atom's energy levels or shells.

Electron Configuration Notation

• Written in the format: 1s² 2s² 2p⁶ 3s² 3p⁶ ..., where:
  • The number indicates the energy level (shell)
  • The letter (s, p, d, f) indicates the subshell
  • The superscript number indicates the number of electrons in the subshell

Aufbau Principle

• States that electrons occupy the lowest available energy levels
• Electrons fill subshells in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, ...

Hund's Rule

• States that when filling degenerate orbitals (orbitals with the same energy level), electrons occupy each orbital singly before pairing up
• This leads to a more stable electron configuration

Pauli Exclusion Principle

• States that no two electrons in an atom can have the same set of quantum numbers (n, l, m, s)
• This means that each orbital can hold a maximum of two electrons with opposite spins

Valence Electrons

• The outermost energy level (valence shell) electrons
• These electrons are involved in chemical bonding and reactions

Electron Configuration and Periodic Trends

• Electron configuration is related to the position of an element in the periodic table
• Elements in the same group (vertical column) have similar electron configurations and chemical properties

Electron Configuration

• Electron configuration is the arrangement of electrons in an atom's energy levels or shells.

Electron Configuration Notation

• Electron configuration notation is written in the format: 1s² 2s² 2p⁶ 3s² 3p⁶...
• In this notation:
  • The number indicates the energy level (shell)
  • The letter (s, p, d, f) indicates the subshell
  • The superscript number indicates the number of electrons in the subshell

Aufbau Principle

• Aufbau principle states that electrons occupy the lowest available energy levels
• Electrons fill subshells in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p,...

Hund's Rule

• Hund's rule states that when filling degenerate orbitals (orbitals with the same energy level), electrons occupy each orbital singly before pairing up
• This leads to a more stable electron configuration

Pauli Exclusion Principle

• Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers (n, l, m, s)
• Each orbital can hold a maximum of two electrons with opposite spins

Valence Electrons

• Valence electrons are the outermost energy level (valence shell) electrons
• These electrons are involved in chemical bonding and reactions

Electron Configuration and Periodic Trends

• Electron configuration is related to the position of an element in the periodic table
• Elements in the same group (vertical column) have similar electron configurations and chemical properties