Bond energies ionic bonds

Bond energy Ionic bonding Ionic compound Covalent bonding Polar covalent bond Electronegativity Dipole moment... 

Section 8.1 bond energy ionic bonding ionic compound Coulomb s law bond length covalent bonding polar covalent bond... 

Other factors which influence the properties of polymers can be illustrated by examining the bond energies or bond strengths and the ionic character of bonds based on Si as contrasted to similar ones based on C. 

Bond energies (actually bond dissociation energies) primarily indicate the susceptibility of the bond to thermal scission, and therefore give evidence of the thermal stability of the macromolecule. The vulnerability of a bond to other reagents, on the other hand, depends mainly on the ionic character of the bond and whether there remain unoccupied orbitals or electron pairs in the molecule, as these will lower the activation energy of reaction with the reagent. The resistance to reduction, oxidation, hydrolysis, etc., decreases with increasing atomic number in every period. Thus hydrocarbons, Cn H in + 2 are not hydrolyzed, but silanes, Si H2n + 2, certainly are. In the latter case there are only four completely filled orbitals of a possible maximum coordination number of six. 

Experimental bond energies and bond distances for the alkali halide molecules are given in Table 2-10. The alkali halides provide the best examples of ionic bonding, since, of all the atoms, the alkali metals have the smallest IP s of course the halogens help by having very high EN s. The most complete electron transfer would be expected... 

Bond energies and bond lengths Ground-state electron configurations Electronegativity values Ionic radii... 

Born-Haber cycle A thermodynamic cycle derived by application of Hess s law. Commonly used to calculate lattice energies of ionic solids and average bond energies of covalent compounds. E.g. NaCl ... 

Structure determines properties and the properties of atoms depend on atomic struc ture All of an element s protons are m its nucleus but the element s electrons are dis tributed among orbitals of varying energy and distance from the nucleus More than any thing else we look at its electron configuration when we wish to understand how an element behaves The next section illustrates this with a brief review of ionic bonding... 

Were we to simply add the ionization energy of sodium (496 kJ/mol) and the electron affin ity of chlorine (—349 kJ/mol) we would conclude that the overall process is endothermic with AH° = +147 kJ/mol The energy liberated by adding an electron to chlorine is msuf ficient to override the energy required to remove an electron from sodium This analysis however fails to consider the force of attraction between the oppositely charged ions Na" and Cl which exceeds 500 kJ/mol and is more than sufficient to make the overall process exothermic Attractive forces between oppositely charged particles are termed electrostatic, or coulombic, attractions and are what we mean by an ionic bond between two atoms... 

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