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Atom video

Atom video. http://www.youtube.com/watch?v=xqNSQ3OQMGI&feature=share. Basic Principle: electrons occupy lowest energy levels available. Aufbau Principle -- “Bottom Up Rule”. Stern-Gerlach Experiment. . . How could an orbital hold two electrons without electrostatic repulsion?.

mckenzie-petersen
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Atom video

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  1. Atom video http://www.youtube.com/watch?v=xqNSQ3OQMGI&feature=share

  2. Basic Principle: • electrons occupy lowest energy levels available

  3. Aufbau Principle -- “Bottom Up Rule”

  4. Stern-Gerlach Experiment •  •  • How could an orbital hold two electrons • without electrostatic repulsion? • Electron spin

  5. 2 ways to write electron configurations spdf Notation • spdf NOTATION • for H, atomic number = 1 • 1 • no. of • electrons • s • 1 • sublevel • value of energy level • Orbital Box Notation • ORBITAL BOX NOTATION for He, atomic number = 2 Arrows show electron spin (+½ or -½) 2  1s 1s

  6. Example: Determine the electron configuration and orbital notation for the ground state neon atom. Pauli exclusion principle • An orbital can contain a maximum of 2 electrons, • and they must have the opposite “spin.”

  7. Write the ground state configuration and the orbital diagram for oxygen in its ground state • Hund’s Rule -

  8. Outer electron configuration for the elements

  9. Using the periodic table to know configurations • Period • 1 • 2 • 3 • 4 • 5 • 6 • 7 • Ne • Ar • Kr • Xe

  10. Valence e’s for “main group” elements

  11. Basic Principle: • electrons occupy lowest energy levels available • Rules for Filling Orbitals • Bottom-up • (Aufbau’s principle) • Fill orbitals singly before doubling up • (Hund’s Rule) • Paired electrons have opposite spin • (Pauli exclusion principle)

  12. Identify examples of the following principles: • 1) Aufbau 2) Hund’s rule 3) Pauli exclusion

  13. Shorthand notation practice Examples ●Aluminum: 1s22s22p63s23p1[Ne]3s23p1 ● Calcium: 1s22s22p63s23p64s2 [Ar]4s2 ● Nickel: 1s22s22p63s23p64s23d8 [Ar]4s23d8 {or [Ar]3d84s2} ● Iodine: [Kr]5s24d105p5 {or [Kr]4d105s25p5} ● Astatine (At): [Xe]6s24f145d106p5 {or [Xe]4f145d106s26p5} • [Noble Gas Core] + higher energy electrons

  14. Electron configuration for As

  15. Note: Not written according to Aufbau, but grouping according to n

  16. Orbital energy ladder • f • d • n = 4 • p • d • s • p • n = 3 • s • p • n = 2 • s • n = 1 • Energy • s

  17. Phosphorus • Symbol:P • Atomic Number:15 • Full Configuration:1s22s22p63s23p3 • Valence Configuration:3s23p3 • Shorthand Configuration:[Ne]3s23p3 •  •  •  •  •  •  •  •  •  • Box Notation •  •  •  •  •  •  •  •  •  • 2s • 1s • 2p • 3s • 3p

  18. Quantum numbers and orbital energiesEach electron in an atom has a unique set of quantum numbers to define it{ n, l, ml, ms } • n = principal quantum number • electron’s energy depends principally on this • l = azimuthal quantum number • for orbitals of same n, l distinguishes different shapes (angular momentum) • ml = magnetic quantum number • for orbitals of same n & l, ml distinguishes different orientations in space • ms = spin quantum number • for orbitals of same n,l & ml, ms identifies the two possible spin orientations

  19. Energy levelSublevel# of orbitals/sublevel n = 1 1s (l = 0) 1 (ml has one value) n = 22s (l = 0) 1 (ml has one value) 2p (l = 1) 3 (ml has three values) n = 33s (l = 0) 1 (ml has one value) 3p (l = 1) 3 (ml has three values) 3d (l = 2) 5 (ml has five values) Quantum numbers and orbital energies Each atom’s electron has a unique set of quantum numbers to define it{ n, l, ml, ms } n = principal quantum number (energy) l = azimuthal quantum number (shape) ml = magnetic quantum number (orientation)

  20. Concept: Each electron in an atom has a unique set of quantum numbers to define it{ n, l, ml, ms } • 21

  21. Quantum numbers: unique set for each e- • s orbitals p orbitals d orbitals f orbitals • l = 0 l = 1l = 2l = 3 • ml = 0ml = -1, 0, 1ml = -2, -1, 0, 1, 2 ml=-3,-2,-1,0,1,2,3 • An s subshellA p subshellA d subshell An f subshell • One s orbitalThree p orbitalsFive d orbitals Seven f orbitals • For n=1 l=0 an s subshell (with 1 orbital) • For n=2 l=0,1 an s subshell and a p subshell (with 3 orbitals) • For n=3 l=0,1,2 an s subshell, a p subshell, a d subshell (with 5 orbitals) • For n=4 l=0,1,2,3 an s subshell, a p subshell, a d subshell, an f subshell (with 7 orbitals)

  22. Electronic configuration of Br 1s2 2s22p6 3s23p63d10 4s24p5 [Ar]3d104s24p5 [Ar] = “noble gas core” [Ar]3d10 = “pseudo noble gas core” (electrons that tend not to react) • Atom’s reactivity is determined by valence electrons • valence e’s in Br:4s24p5 • highest n electrons

  23. Valence e- shells for transition metalsv.main group elements • d orbitals not included • in valence shell • (pseudo noble gas cores) • d orbitals sometimes • included in valence shell

  24. Rule-of-thumb for valence electrons Examples ●Sulfur: 1s22s22p63s23p4 or [Ne]3s23p4 valence electrons:3s23p4 ● Strontium: [Kr]5s2 valence electrons:5s2 ● Gallium: [Ar]4s23d104p1 valence electrons:4s24p1 ● Vanadium: [Ar]4s23d3 valence electrons:4s2or3d34s2 • Identify all electrons at the highest principal quantum number (n) • Use on exams, • but recognize • limitations • Use Table 8.9 • for online HW

  25. Selenium’s valence electrons • Written for increasing energy: • Pseudo noble gas core includes: • noble gas electron core • d electrons (not very reactive)

  26. Core and valence electrons in Germanium • Written for increasing energy: • Pseudo noble gas core includes: • noble gas core • d electrons

  27. d-block: some exceptions to the Aufbau principle • Fig. 8.9: Use this table for online homework

  28. Electron spin & magnetism • For the ground state oxygen atom: • spdf configuration: • orbital box notation: Paramagnetic: atoms with unpaired electrons that are weakly attracted to a magnet. Diamagnetic: atoms with paired electrons that are not attracted to a magnet.

  29. Apparatus for measuring magnetic properties

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