7/19/2009. Source: Corbis. Mendeleev's early periodic table, published in 1872

Transcription

1 Atomic and Molecular Structure Dmitri Ivanovich Mendeleev Source: Corbis Mendeleev's early periodic table, published in 187 1

2 ATOMS CHEMISTRY MASS CHARGE nucleus proton 1 +1 neutron 1 0 electron 0-1

3 CHEMISTRY CHEMISTRY Most chemistry is in the electrons Most chemistry is in the electrons (the outer shell electrons) CHEMISTRY Most chemistry is in the electrons (the valence electrons) 3

4 Electronic transitions in the Bohr model for the hydrogen atom E h (wavelength) x (frequency) = speed [m/s] λν = c [10 8 m/s] 4

5 E = h ν A change between two discrete energy levels emits a photon of light. E h E h 5

6 A typical aerial shell used in a fireworks display Massive star in Pistol Nebula QUANTUM NUMBERS to label electrons n Shell 1 1,, Source: NASA

7 QUANTUM NUMBERS to label electrons n Shell 1 1,, l Angular momentum 0,..,n-1 Three representations of the hydrogen 1s 7

8 Representation of the p orbitals. Representation of the p orbitals. A cross section of the electron probability distribution for a 3p orbital. X X Representation of the 3d orbitals 8

9 X Representation of the 3d orbitals X Representation of the 4f orbitals in terms of their boundary surfaces. QUANTUM NUMBERS to label electrons QUANTUM NUMBERS to label electrons n Shell 1 1,, n Shell 1 1,, l Angular 0,..,n-1 momentum m l Direction of l -l,.,+l l Angular 0,..,n-1 momentum m l Direction of l -l,.,+l s Spin ±½ 9

10 QUANTUM NUMBERS to label electrons QUANTUM NUMBERS to label electrons So how many different electrons are possible for a given l value? l m l spin total s 0 0 ±½ 1 p 1-1,0,1 ±½ d -,-1,0,1, ±½ 10 f 3-3, -,-1,0,1,,3 ±½ 14 X X

11 X X QUANTUM NUMBERS to label electrons Wolfgang Pauli n Shell 1 1,, l Angular 0,..,n-1 momentum m l Direction of l -l,.,+l s Spin ±½ 11

12 Wolfgang Pauli PAULI PRINCIPLE NO TWO ELECTRONS SHALL HAVE THE SAME SET OF QUANTUM NUMBERS PAULI PRINCIPLE NO TWO ELECTRONS SHALL HAVE THE SAME SET OF QUANTUM NUMBERS Consequence: AUFBAU 1s 1 1

13 1s 1s s 1 1s s 1s s p 1 13

14 1s s p 1s s p 1s s p 3 14

15 1s s p 4 1s s p 5 1s s p 1s s p 3s 1 15

16 1s s p 3s 1s s p 3s 3p 1 1s s p 3s 3p 1s s p 3s 3p 3 1

17 1s s p 3s 3p 4 1s s p 3s 3p 5 Electron configurations for potassium through krypton. 1s s p 3s 3p 17

18 The orbitals filled for elements in various parts The orbitals filled for elements in various parts X Copyright Houghton Mifflin Company. All rights reserved. 1a 71 Copyright Houghton Mifflin Company. All rights reserved. 1a 7 18

19 X The periodic table with atomic symbols, atomic numbers, and partial electron configurations Copyright Houghton Mifflin Company. All rights reserved. 1a 73 The periodic table with atomic symbols, atomic numbers, and partial electron configurations X The periodic table with atomic symbols, atomic numbers, and partial electron configurations 19

20 The periodic table with atomic symbols, atomic numbers, and partial electron configurations The periodic table with atomic symbols, atomic numbers, and partial electron configurations A form of the periodic table recommended by IUPAC CHEMISTRY Full shells make the happiest atoms 0

21 CHEMISTRY Special names for groups in the periodic table Full shells make the most stable atoms Special names for groups in the periodic table (cont d) X 1

22 The values of first ionization energy for the elements in the first five periods. The values of first ionization energy for the elements in the first five periods. The electron affinity for atoms among the first 0 X elements that form stable, isolated X- ions.

23 The radius of an atom (r) is defined as half the distance between the nuclei in a molecule consisting of identical atoms. X Radial probability distributions Atomic radii (in picometers) for selected atoms. 3

24 X 4