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ATOMIC ELECTRON CONFIGURATIONS AND PERIODICITY

ATOMIC ELECTRON CONFIGURATIONS AND PERIODICITY. Arrangement of Electrons in Atoms. Electrons in atoms are arranged as SHELLS (n) SUBSHELLS (l) ORBITALS (m l ). QUANTUM NUMBERS. n ---> shell 1, 2, 3, 4, ... l ---> subshell 0, 1, 2, ... n - 1

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ATOMIC ELECTRON CONFIGURATIONS AND PERIODICITY

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  1. ATOMIC ELECTRON CONFIGURATIONS AND PERIODICITY

  2. Arrangement of Electrons in Atoms Electrons in atoms are arranged as SHELLS (n) SUBSHELLS (l) ORBITALS (ml)

  3. QUANTUM NUMBERS n ---> shell 1, 2, 3, 4, ... l ---> subshell 0, 1, 2, ... n - 1 ml ---> orbital -l ... 0 ... +l ms ---> electron spin +1/2 and -1/2

  4. Pauli Exclusion Principle No two electrons in the same atom can have the same set of 4 quantum numbers. That is, each electron has a unique address.

  5. See “Toolbox” for Electron Configuration tool.

  6. Electron Filling OrderFigure 8.5

  7. spdf notation for H, atomic number = 1 1 no. of s 1 electrons value of l value of n Writing Atomic Electron Configurations Two ways to write configs. One is called spdf notation.

  8. Writing Atomic Electron Configurations Other is called the orbital box notation. One electron has n = 1, l = 0, ml = 0, ms = + 1/2 Other electron has n = 1, l = 0, ml = 0, ms = - 1/2

  9. Lithium Group 1A Atomic number = 3 1s22s1 3 total electrons

  10. Beryllium Group 2A Atomic number = 4 1s22s2 ---> 4 total electrons

  11. Boron Group 3A Atomic number = 5 1s2 2s2 2p1 ---> 5 total electrons

  12. Carbon: Group 4A Atomic number = 6 1s2 2s2 2p2 ---> 6 total electrons Here we see for the first time HUND’S RULE. Electrons in orbitals having the same energy are placed singlyas long as possible.

  13. Nitrogen Group 5A Atomic number = 7 1s2 2s2 2p3 ---> 7 total electrons HUND’S RULE. When placing electrons in the same energy, we place them singly as long as possible.

  14. Oxygen Group 6A Atomic number = 8 1s2 2s2 2p4 ---> 8 total electrons HUND’S RULE. When placing electrons in the same energy, place them singlyas long as possible.

  15. Fluorine Group 7A Atomic number = 9 1s2 2s2 2p5 ---> 9 total electrons

  16. Neon Group 8A Atomic number = 10 1s2 2s2 2p6 ---> 10 total electrons Note that we have reached the end of the 2nd period, and the 2nd shell is full!

  17. Sodium Group 1A Atomic number = 11 1s2 2s2 2p6 3s1 or “neon core” + 3s1 [Ne] 3s1 (uses rare gas notation) All Group 1A elements have [core]ns1 configurations.

  18. Calcium Group 2A Atomic number = 20 1s2 2s2 2p6 3s2 3p6 4s2 [Ar] 4s2 All Group 2A elements have [core]ns2 configurations n is the period number.

  19. Aluminum Group 3A Atomic number = 13 1s2 2s2 2p6 3s2 3p1 [Ne] 3s2 3p1 Group 3A elements [core] ns2 np1 n is the period number.

  20. Phosphorus Group 5A Atomic number = 15 1s2 2s2 2p6 3s2 3p3 [Ne] 3s2 3p3 All Group 5A elements have [core ] ns2 np3 configurations where n is the period number.

  21. Transition MetalsTable 8.4 All 4th period elements have the configuration [argon] nsx (n - 1)dy and so are “d-block” elements. Chromium Iron Copper

  22. Lanthanides and Actinides All these elements are “f-block” elements. Cerium [Xe] 6s2 5d1 4f1 Uranium [Rn] 7s2 6d1 5f3

  23. Electron Configurations and the Periodic Table

  24. “Your Best Friend” • Periodic table

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