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Electron Configurations. You will need: Your homework from Friday (Quantum Mechanical Model in last week’s packet) Your homework from last night (Electron Configuration Guided Reading in this week’s packet) Anything that you see in white, you should write down . Bohr Model of Hydrogen.
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Electron Configurations You will need: Your homework from Friday (Quantum Mechanical Model in last week’s packet) Your homework from last night (Electron Configuration Guided Reading in this week’s packet) Anything that you see in white, you should write down
Bohr Model of Hydrogen Nucleus e e Possible electron orbits Zumdahl, Zumdahl, DeCoste, World of Chemistry2002, page 331
Bohr Model of Hydrogen • Bohr model = epic fail for all other elements e e
The Quantum Mechanical Model • 2 parts of an atoms • Nucleus • Electron cloud • Where the probability of finding an electron is high • Drawn as a fuzzy cloud • The cloud is more dense where the probability of finding the electron is high. Electron cloud Less likely to find an electron More likely to find an electron Nucleus
The Quantum Mechanical Model • Atomic Orbitals • Space around the nucleus • High probability of finding an electron • Has a specific energy level • Has a specific sublevel • Sublevels have different shapes • Further describes where an electron is likely to be found
The Quantum Mechanical Model Atomic orbital shapes: AKA: Angular momentum quantum number S orbital Angular momentum quantum number (l) = 0
The Quantum Mechanical Model Atomic orbital shapes: P orbitals Angular momentum quantum number (l) = 1
The Quantum Mechanical Model Atomic orbital shapes: D orbitals Angular momentum quantum number (l) = 2
The Quantum Mechanical Model Atomic orbital shapes: F orbitals Angular momentum quantum number (l) = 3
Think-Pair-Share • Turn to your neighbor and… • Explain what an orbital is • List the 4 shapes of atomic orbitals
Vocabulary • Quantum numbers: tell us the properties of atomic orbitals and the properties of electrons in the orbitals • Principle quantum number • Symbol: n • The energy level that an electron occupies • Angular momentum quantum number • Symbol: l • The shape of the orbital • Spin quantum number • +1/2 or -1/2 • Spin state of an electron
Electron Configurations • Electron configuration: • The arrangement of electrons in an atom • The lowest-energy arrangement of the electrons for each element is called the element’s ground-state electron configuration
Rules for writing electron configurations • Aufbau principle: • An electron occupies the orbital of lowest-energy first 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f
Rules for writing electron configurations • Hund’s rule: • Electrons occupy equal energy orbitals one at the time • The electrons in each orbital have the same spin • School bus rule 2px 2py 2pz
Rules for writing electron configurations • Pauli exclusion principle: • Electrons in the same orbital must have different spins 2px 2py 2pz
Think Pair Share • Turn to your neighbor and explain the three rules for electron configurations in your own words
Orbital Diagram p. 105 Box = orbital Up and down arrow = electrons with opposite spins Arrow = electron
Electron Notations • Orbital notation • Lines (or boxes) represent orbitals • Arrows represent electrons He
Orbital Notation Li = # of electrons = 3 • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Notations • Electron configurations • Written in the following order: • Number of energy level • Letter of sublevel • Number of electrons in each sublevel written as a superscript Number of electrons 1s2 Energy level Sublevel Number of electrons Energy levels 1s22s22p6 Sublevels
Electron Configurations Li =1 • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations Li =1s • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations Li =1s2 • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations Li =1s22 • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations Li =1s22s • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations Li =1s22s1 # of electrons = 3 • Aufbau principle: an electron occupies the orbital of lowest-energy first
Electron Configurations # of electrons = 6 C = • Hund’s rule: electrons occupy equal energy orbitals one at the time with the same spin
Electron Configurations C = 1 • Hund’s rule: electrons occupy equal energy orbitals one at the time with the same spin
Electron Configurations C = 1s • Hund’s rule: electrons occupy equal energy orbitals one at the time with the same spin
Electron Configurations C = 1s2 • Hund’s rule: electrons occupy equal energy orbitals one at the time with the same spin