120 likes | 150 Vues
STRUCTURE: Bonding. S.C. BAYNE, 1 J.Y. Thompson 2 1 University of Michigan School of Dentistry, Ann Arbor, MI 48109-1078 sbayne@umich.edu 2 Nova Southeastern College of Dental Medicine, Ft. Lauderdale, FL 33328-2018 jeffthom@nova.edu. 3s. 2p. 2s. 1s. INTRODUCTION
E N D
STRUCTURE: Bonding S.C. BAYNE,1 J.Y. Thompson2 1University of Michigan School of Dentistry, Ann Arbor, MI 48109-1078 sbayne@umich.edu 2Nova Southeastern College of Dental Medicine, Ft. Lauderdale, FL 33328-2018 jeffthom@nova.edu
3s 2p 2s 1s INTRODUCTION Quick review of elements and bonding. SODIUM AN=11 Atomic Weight = 22.99
PRIMARY BONDING Types. IONIC BONDING COVALENT BONDING METALLIC BONDING
PRIMARY BONDING Formation of bonds.
BONDING CHARACTER Mixed bonding character is the rule rather than the exception.
Theory of Electronegativity Distinguishing the degree of ionic-covalent bonding character. Li Be B C N O F 1.5 1.5 2.0 2.5 3.0 3.5 4.0 Na Mg Al Si P S Cl 0.9 1.2 1.5 1.5 2.1 2.5 3.0 K Ca Sc Ti V Cr Mn Fe Co Na Cu Zn Ga Ge As Se Br 0.8 1.0 1.3 1.5 1.5 1.5 1.5 1.8 1.8 1.8 1.9 1.6 1.6 1.8 2.0 2.4 2.8 Rb Sr Y Zr Nb Mo Tc Ru Th Pd Ag Cd In Sn Sb Te I 0.8 1.0 1.2 1.4 1.5 1.8 1.9 2.2 2.2 2.2 1.9 1.7 1.7 1.8 1.9 2.1 2.5 Cs Ba La/Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At 0.7 0.9 1.15 1.3 1.5 1.7 1.9 2.2 2.2 2.2 2.4 1.9 1.8 1.8 1.9 2.0 2.2 Fr Ra Ac Th Pa U Np/No 0.7 0.9 1.1 1.3 1.5 1.7 1.3 TABLE OF ELECTRONEGATIVITIES
3s EMPTY 3s STATES 2p 3s 2s FILLED 3s STATES 1s Valence Band ENERGY ENERGY FILLED 2d STATES 2p FILLED 2s STATES 2s FILLED 1s STATES 1s FAR CLOSE BAND THEORY ATOMIC SPACING BAND STRUCTURE Energy band types and properties. SODIUM ATOM
Conduction Band Conduction Band Conduction Band 4 4 ENERGY GAP 3 ENERGY GAP 3 3 Valence Band Valence Band Valence Band 2 2 2 1 1 1 BAND STRUCTURE Energy band types and properties. CONDUCTOR SEMI-CONDUCTOR INSULATOR
H H H A. B. O C O C O C H H H H H O CH 2 H C O C O H H H SECONDARY BONDING Hydrogen bonding, London disperson forces, and chelation.
CHELATION BONDING Hydrogen bonding, London disperson forces, and chelation.
QUICK REVIEW Review of bonding types. • Which type of ELEMENT composes most of the periodic table? • METAL • Which PRIMARY BONDING type is involved with polymer? • COVALENT • What BONDING CHARACTER is associated with NiTi? • IONIC, COVALENT, but MOSTLY METALLIC. • How do you characterize a SEMI-CONDUCTOR using band theory? • VALENCE BAND IS FULL, BUT SMALL ENERGY GAP. • What SECONDARY BONDING type includes ionic and covalent bonding? • CHELATION