Electron Configuration and Atomic Orbitals

Electron Configuration

• The arrangement of electrons in an atom, which determines the chemical properties of an element
• Described by the Aufbau principle, Pauli's Exclusion Principle, and Hund's Rule
• Electron configuration is written in a shorthand notation, such as 1s2 2s2 2p6 for Ne (Neon)
• Energy levels (shells) are divided into subshells (s, p, d, f) with specific capacities
• Valence electrons are the outermost electrons involved in chemical bonding

Ionization Energy

• The energy required to remove an electron from an atom in its ground state
• Measured in kJ/mol (kilojoules per mole)
• Ionization energy increases:
  • Across a period (left to right) due to increasing nuclear charge
  • Down a group (top to bottom) due to increasing atomic size and shielding
• First ionization energy is the energy required to remove the first electron, subsequent ionization energies are for removing additional electrons

Atomic Orbitals

• A mathematical description of the distribution of electrons within an atom
• Orbital shapes: s (spherical), p (dumbbell), d (four-leaf clover), f (complex)
• Orbital types:
  • s orbitals: spherical, symmetrical, and can hold up to 2 electrons
  • p orbitals: dumbbell-shaped, oriented along x, y, and z axes, and can hold up to 6 electrons
  • d and f orbitals: more complex shapes, and can hold up to 10 and 14 electrons, respectively
• Orbitals are combined to form hybrid orbitals, which are used to describe molecular bonding and shape

Test your understanding of electron configuration, atomic orbitals, and ionization energy. Learn how to describe the arrangement of electrons in an atom and how it affects chemical properties.