1 / 14

Periodic Properties

Periodic Properties. nuclear charge. electron configurations. properties. hydrogen atom . 1 electron. 1 s 1. Z = 1. 1. 1. to remove e -. n f = ∞. -. E =. - R H. Z 2. n f 2. n i 2. from ground state. n i = 1. E =. 2.178 x 10 -18 J. x 6.022 x 10 23 atoms. = 1311 kJ.

andres
Download Presentation

Periodic Properties

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Periodic Properties nuclear charge electron configurations properties hydrogen atom 1 electron 1s1 Z = 1 1 1 to remove e- nf = ∞ - E = - RH Z2 nf2 ni2 from ground state ni = 1 E = 2.178 x 10-18 J x 6.022 x 1023 atoms = 1311 kJ atom mol mol Ionization Energy, I

  2. + 2+ H 1s1 Z = +1 E = 1311 kJ/mol He+ 1s1 Z = +2 E = 5250 kJ/mol - - 1 1 = 5250 kJ/mol - E = - RH Z2 nf2 ni2 higher nuclear charge lowers orbital energy stabilizes system systems with more than 1 electron studied experimentally ionization reactions

  3. - 2+ 2+ 1. Effect of 2 electrons in same orbital He+ 1s1 E = 5250 kJ/mol He 1s2 E = 2372 kJ/mol same nuclear charge Z = +2 orbital energy higher - e- e- repulsion - less stable easier to remove e-

  4. 2s 2s 1s 1s 3+ 3+ 2. Effect of electrons in different orbital Li ground state 1s2 2s1 E = 520 kJ/mol excited state 2s1 Li2+ E = 2954 kJ/mol same nuclear charge Z = +3 - - - - Zeff < Z inner electrons shielding charge

  5. 2s 2p 1s 1s 3+ 3+ 3. Effect of orbital shape Li ground state 1s2 2s1 E = 520 kJ/mol excited state 1s2 2p1 Li E = 341 kJ/mol same nuclear charge Z = +3 - - - - - - s orbitals penetrating lower energy

  6. Electrostatic interactions determine orbital energies 1. Greater nuclear charge (Z) lowers energy electrons more difficult to remove 2. Electron-electron repulsion raise energy electrons easier to remove electrons shield Z inner electrons shield better 3. Orbitals with more penetration lower energy electrons more difficult to remove s < p < d < f

  7. Ionization Energy energy required to remove an e- from gas phase atoms X (g)  X+(g) + e- first ionization energy I1 X+ (g)  X2+(g) + e- second ionization energy I2 lowest I1 Cs n = 6 He highest I1 n = 1

  8. I1 increase Z increases shielding stays same adding valence e- core e- unchanged I1 decrease Zeff decreases more shielding e- core e-

  9. 2p 2p 2s 2s 1s 1s 5+ 10+ - - - - - - - - - - - - - - - B Ne

  10. 2p 2s 2s 1s 1s 4+ 5+ - - - - - - - - - B Be N O e- e- repulsion

  11. Second Ionization Energy I2 I1 I7 I2 I3 I4 I5 I6 4560 Na 495 Mg 735 1445 7730 580 1815 11,600 Al Si 780 1575 16,100 P 1060 1890 21,200 S 2260 1005 27,000 very difficult to remove Cl 1255 2295 core electrons Ar 1527 2665

  12. Atomic Radius 143 pm Al metallic radius Cl 100 pm covalent radius C-Cl 177 pm Cl 100 pm 77 pm C

  13. Atomic Radius increase in size n dominates decrease in size Zeff dominates

  14. - + Ionic sizes e- isoelectronic series same # electrons 46 e- ions get smaller +49 +50 +51

More Related