Chem 121 1st Edition Lecture 9 Outline of Last Lecture I. Periodic Law and Periodic TableII. Properties of a GroupIII. Classification of ElementsIV. Electron- Spin and the Pauli PrincipleV. Multi- Electron AtomsVI. Sublevel Energy SplittingVII. Aufbau Principle and Electron ConfigurationOutline of Current Lecture VIII. Aufbau Principle and Electron Configuration ContinuedIX. Electron Configuration and Periodic TableCurrent LectureAufbau Principle and Electron Configuration- Boron (Z=5) 5 electronso Valence electrons (Electrons in outermost shell (largest n): 3o 1s22s22p1- Carbon (Z=6) 6 electronso Valence electrons: 4o 1s22s22p2o Group # 4A- Nitrogen (Z=7) 7 electronso Valence electrons: 5o 1s22s22p3o Group # 5A- Oxygen (Z=8) 8 electronso Valence electrons: 6o 1s22s22p4- Fluorine (Z=9) 9 electronso Valence electrons: 7o 1s22s22p5o Group # 7A- Neon (Z=10) 10 electrons These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Valence electrons: 8o 1s22s22p6Electron Configuration and Periodic Table- Electron Configuration: the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.- Electron Configuration within groups (as pictured below)o Period begins with ns, ends at np (except He)o Same group, Same electron configuration in outermost shello **From notes: “By losing, gaining, or sharing an electron, atoms must have electron configuration as Noble Gases Elements to be stable.” –Octet Ruleo Octet Rule was used to explain the chemistry of elements- Aufbau Diagram (below)o Aufbau Diagram- Order of filling orbitalso n - outermost occupied shell (period)- Anomalies in filling electrons- Half and complete filled d sublevel are more stable in energy- B-Group elements (transition elements)o d electrons occupies individual d orbital with parallel spin first- Hund’s Rule - Blocks on periodic tableo s-block: Group I A (ns1), II A (ns2)o p-block: Group III A – VIII A (ns2np1- ns2np6)o d-block: Transition metals ((n-1)d1ns2- (n-1)d10ns2)o f-block: Lanthanides & Actinides (4f &5f)- Element in a group: Same outer electron configuration and similar chemical properties- Element in a period: Same outermost shell (n), same high occupied energy level- Categories of electrons:o Inner (core) electrons: electrons in lower energy levelso Valence electrons: outmost electrons that affect large chemical propertiesof the elementso Main groups: highest ns + np = group