University:
Bradley University
Course:
CHM 100 | Fundamentals of General Chemistry
Academic year:

2021
Views:

15

Pages:

21
Author:

Remington Spence

Section 3 Electron Configurations Aufbau Principle Electrons occupy lowest energy orbital available – Within a principal energy level: s, p, d, f – Orbitals within one principal energy level can overlap orbitals of another Electron Filling Order Periodic Table Helps! Pauli Exclusion Principle – Maximum of 2 electrons in an orbital, but only if they have opposite spin. Hund’s rule – Electrons with same spin must occupy each equal energy orbital before additional electrons with opposite spins can occupy the same orbital. 1) Electron Configuration Notation • Pattern of: number, letter, superscript subshell designation # of electrons in subshell Electron Configuration Notation • Ex: N – # of electrons? • Use the fill order. Start with the lowest energy, fill to capacity, go to next lowest energy, etc. Stop when you run out of electrons. – Superscripts = total electrons Electron Configuration Notation • You try … Zinc Electron Configuration Notation • Answer: 1s2 2s22p6 3s23p6 4s23d10 2) Noble Gas Notation • Shorthand – Find the noble gas closest to the element (without going over). – Ex: For Gold (79): Xenon (54) – We write [Xe] and start counting from there – The first orbital after xenon is 6s Noble Gas Notation 2 14 9 • [Xe]6s 4f 5d • Check: (Xe’s atomic number) 54 + 2 + 14 + 9 = 79 (gold’s Atomic number)! You Try… • Silver 3) Orbital Diagrams • Show the orbital distributions of electrons related to a sublevel • Include a line for each orbital • = orbital with 1 electron • = orbital with 2 electrons Orbital Diagrams • Nitrogen: 1s22s22p3 – Write notation of N 1s 2 s 2 p 2 p 2 p – Then we fill them with electrons using the Aufbau principle, Pauli exclusion principle, and Hund’s law      1s 2s 2 p 2 p 2 p Orbital Diagrams • You try another example: Cu Orbital Diagrams • Answer                1s 2s 2 p 2 p 2 p 3s 3 p 3 p 3 p 4s 3d 3d 3d 3d 3d 4) Electron Dot Structures • Valence electrons – Electrons in outermost energy level. – Responsible for chemical properties Electron Dot Structures • • • • Valence electrons only Place ‘dots’ around element symbol 4 sides of element = orbitals Fill these orbitals one at a time (Hund’s) Electron Dot Structures Assignment • P.141 #23(yellow box), 26, 28 • P.147 #81