Electron Configuration

• What does Aufbau's principle state?

  Electrons fill lowest energy states first
• What is the purpose of the matrix created for electron energies?

  • To remember the direction of higher energy orbitals
  • To simplify understanding of electron configurations
• How many primary exceptions to Aufbau's rule are mentioned?

  Two primary exceptions
• Which electron configuration ending indicates the first exception?

  Ending in d9
• Which elements are specifically mentioned for the d9 exception?

  Copper, silver, and gold
• Why does the trend not continue beyond gold?

  The reasoning is more complicated
• What is the electron configuration of copper with 29 electrons?

  1s2 2s2 2p6 3s2 3p6 4s2 3d9
• What happens to the d9 orbital in copper?

  It prefers to become d10 for stability
• Why do atoms prefer a d10 configuration?

  It stabilizes the electron cloud significantly
• What is the second exception related to?

  Half-filled d orbitals
• What is the expected electron configuration for chromium with 24 electrons?

  1s2 2s2 2p6 3s2 3p6 4s2 3d4
• What adjustment is made to chromium's electron configuration?

  One electron is pulled from the s orbital
• Why is the adjusted configuration for chromium more stable?

  It half-saturates the d orbital
• What are the main reasons for exceptions in electron configurations?

  • Atoms seek greater stability
  • Atoms aim to hold onto electrons better
• Which elements should students recognize for electron configuration exceptions?

  Chromium, molybdenum, copper, silver, gold
• What should students do if they have questions about the video content?

  Leave a comment for clarification
• What is suggested for supporting the channel?

  Check out YouTube memberships or Patreon
• What is the purpose of the links provided in the description?

  To reference electron configurations and exceptions
• What are the key concepts related to electron configuration exceptions?

  • Aufbau's principle
  • d9 and half-filled d orbital exceptions
  • Stability of electron configurations
  • Specific elements: chromium, molybdenum, copper, silver, gold
• What is the focus of video five in Chemistry Essentials?

  Electron configurations
• What does electron configuration represent?

  Distribution of electrons in atoms or ions
• How can ionization energy be defined?

  Energy needed to remove an electron
• How can we quantify ionization energy?

  Using Coulomb's law
• What are core electrons?

  Electrons in inner shells of an atom
• What are valence electrons?

  Electrons in the outermost shell
• What effect do core electrons have on valence electrons?

  They shield valence electrons from the nucleus
• What is the ionization energy of hydrogen approximately?

  12 eV
• Why does helium have a higher ionization energy than hydrogen?

  Helium has more protons attracting electrons
• What happens to ionization energy when comparing helium and lithium?

  Lithium has lower ionization energy due to shielding
• What is the trend in ionization energy across the periodic table?

  It generally increases from left to right
• What is the significance of noble gases in ionization energy charts?

  Noble gases have complete electron shells
• How are electrons organized in atoms?

  Into shells, subshells, and orbitals
• What is the maximum number of electrons in an S subshell?

  2 electrons
• How many orbitals are in a P subshell?

  3 orbitals
• What is the maximum number of electrons in a D subshell?

  10 electrons
• What is the maximum number of electrons in an F subshell?

  14 electrons
• How would you write the electron configuration for hydrogen?

  1s¹
• What is the electron configuration for boron?

  1s² 2s² 2p¹
• What is the electron configuration for neon?

  1s² 2s² 2p⁶
• What is the electron configuration for sodium?

  1s² 2s² 2p⁶ 3s¹