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Flashcards

Group 16 - General Characteristics

Nancy Mathew Chemistry CBSE Central Board of Secondary Education Inglês 27 flashcards

Group 16 - General Characteristics

Flashcards do conjunto (27)

  1. 1What are O, S, Se, Te, Po commonly called?What are O, S, Se, Te, Po commonly called?
  2. 2Naturally existing sulphatesGypsum - CaSO4.2H20
    Epsom Salt - MgSO4.7.H20
    Baryte - BaSO4    Naturally existing sulphates
  3. 3Naturally occurring SULPHIDESGalena - PbS
    Zinc blende - ZnS
    Copper pyrites - CuFeS2    Naturally occurring SULPHIDES
  4. 4General electronic configurationns2 np4
    (6 valence electrons)
  5. 5Atomic/ Ionic radiiIncreases down the group
    (more shells)    Atomic/ Ionic radii
  6. 6Ionisation enthalpy (energy to remove an e-)Decreases down the group
    lesser than gr 15 (1/2-filled p-orbitals)    Ionisation enthalpy (energy to remove an e-)
  7. 7Electron gain enthalpy (energy to gain an e-)More negative to less negative
  8. 8Why is the electron gain enthalpy of oxygen less (-ve) than sulphur?Compact nature of oxygen atom
  9. 9Electronegativity (ability to pull an e- pair towards itself)Decreases down the group
    (hence metallic character increases from O to Po)
  10. 10Metallic characterO, S - Non-metals
    Se, Te - Metalloids
    Po - Metal
  11. 11Radioactive element(s)PoloniumRadioactive element(s)
  12. 12Melting and boiling points (trend)Increase down the group
    (increase in size)
  13. 13Why is there a large difference between the melting and boiling points of Oxygen and Sulphur?Due to difference in atomicity
    Oxygen - O2 (diatomic)
    Sulphur - S8 (Polyatomic)    Why is there a large difference between the melting and boiling points of Oxygen and Sulphur?
  14. 14Oxidation states exhibited-2 - stability decreases down the group
    +2
    +4 - stability increases down the group (inert pair effect) - covalent bonding
    +6 - stability decreases down the group - covalent bonding
  15. 15When does oxygen exhibit +2 oxidation state?Oxygen has high electronegativity, hence exhibits negative ox. states (-2)
    In OF2 - +2
  16. 16Oxidation states of S, Se, Te with O, Fwith oxygen - +4
    with fluorine - +6
  17. 17Anomalous behaviour of oxygen is due to...1. Small size
    2. High electronegativity
  18. 18Why is there strong hydrogen bonding in H2O, but not in H2S? (H2O is liquid while H2S is gaseous)1. Small size
    2. High electronegativity
  19. 19Covalency of Oxygen, reasonLimited to 4
    Absence of d-orbitals
  20. 20Hydrides and their trendsH2O, H2S, H2Se, H2Te, H2Po
    1. Acidity -> (decrease in bond dissociation enthalpy, more ability to release H+)
    2. Thermal stability -> ''
    3. Strength of reducing agent ->
    (except H2O)
  21. 21Types of oxidesEO2 - reducing strength decreases down the group (SO2 reducing, TeO2 - oxidising)
    EO3 - S, Se, Te
    (both are acidic in nature)
  22. 22HalidesEX2, EX4, EX6
  23. 23Stability of halidesstability - F > Cl > Br > I
  24. 24stable hexahalides and their structurehexafluorides , octahedral
    SF6 is most stable (steric reasons)
  25. 25Structure and hybridisation of tetrafluoridessp3d - Trigonal bipyramidal with one lp in the equatorial position (SEE - SAW)
  26. 26Dichlorides, dibromides Structure, hybridisationHybridisation: sp3
    Structure: Tetrahedral
    DIMERIC in nature
    (S2F2, S2Cl2, S2Br2, Se2Cl2, Se2Br2)    Dichlorides, dibromides Structure, hybridisation
  27. 27Disproportionation in dimeric halides+2 +4 0
    2Se2Cl2 ->SeCl4 +3Se

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CBSE Central Board of Secondary Education Chemistry FlashCards sobre Group 16 - General Characteristics, criado por Nancy Mathew em 07-12-2016.
Criado por
Nancy Mathew
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