Chemical Bonding & Molecular Structure |
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I. Chemical Bonding |
A. Bond Formation |
1. Electronegativity |
2. Bond Character |
3. Ionic Bonds |
4. Covalent Bonds |
5. Metallic Bonds |
6. Polyatomic Ions |
B. Particle Sizes |
1. Ionic Radii |
2. Covalent Radii |
3. Van der Waals Radii |
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II. Molecular Structure |
A. Bonds in Space |
1. Electron Distribution |
2. Electron Pair Repulsion |
B. Hybrid Orbitals |
1. Sigma & Pi Bonds |
2. Multiple Bond Molecular Shapes |
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III. Polar Molecules |
A. Molecular Attractions |
1. Polarity |
2. Weak Forces |
B. Coordination Chemistry |
1. Ligand and Complex Ions |
2. Coordination Compounds |
Bonds between
Hydrogen and Halogens |
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Bond |
Bond Strength (kJ/mol) |
Electronegativity Difference |
H – F |
568.1 |
1.90 |
H – Cl |
431.951 |
0.63 |
H – Br |
366.25 |
1.54 |
H – I |
298.32 |
0.01 |
Character
of Bonds |
||||||||||
Electronegativity Difference |
0 |
0.65 |
0.94 |
1.19 |
1.43 |
1.67 |
1.91 |
2.19 |
2.54 |
3.03 |
Percent Ionic Character
(%) |
0 |
10 |
20 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
Percent Covalent Character (%) |
100 |
90 |
80 |
70 |
60 |
50 |
40 |
30 |
20 |
10 |
Chemical
Bond Summary |
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Bond
Type |
Generally
Formed Between |
Bond
Formed by |
Properties
of Bond Type |
Examples |
Covalent |
Atoms of nonmetallic elements of similar electronegativity |
Sharing of electron pairs |
Stable nonionizing molecules – not conductors of electricity |
OF2, C2H6, SiC, ASCl3, GeCl4, C, Si |
Ionic |
Atoms of metallic and nonmetallic elements of widely different electronegativities |
Electrostatic attraction between ions resulting from transfer of electrons |
Charged ions in gas, liquid, and solid. Solid is electrically nonconducting. Gas and liquid are conductors. High melting points. |
NaCl, K2O, BaS, LiH, CdF2, BaBr2, ErCl3, CdO, Ca3N2 |
Metallic |
Atoms of metallic elements |
Delocalized electron (mobile electron) cloud around atoms of low electronegativity |
Electrical conductors in all phases, luster, very high melting points. |
Na, Au, Cu, Zn, Ac, Be, Gd, Fe |
Weak
Forces Summary |
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van der Waals forces |
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Type of Force |
Hydrogen bonds |
Dispersion forces |
Dipole Interactions |
Substances Exhibiting Force |
Very polar polar covalent bond |
Nonpolar molecules |
Polar covalent molecules |
Source of The force |
Hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared pair of another electronegative atom. |
Weak electrical fluctuations which destroy spherical symmetry of electronic fields around atoms |
Electric attraction between dipoles resulting from polar bonds |
Hydrogen bonds > Dipole Interactions > Dispersion forces |
Strongest ––––––––––––––––––––––––––––––> Weakest