# Chemical Bonding I_ Lewis Threory by malj

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```									           Chapter 9
Chemical Bonding I: Lewis Theory
Potential Energy versus Distance
Lattice Energies
Chapter 9: Examples –
Formation of Ionic Compounds
9.1.   Calculate the lattice energy for the formation
of sodium chloride from it’s elements. Given:
Na (s) → Na (g)               +107.3 kJ/mol
Na (g) → Na+(g) + 1 e-        +495.8 kJ/mol
½ Cl2 (g) → Cl (g)            +122 kJ/mol
Cl (g) + 1 e- → Cl- (g)       -348.6 kJ/mol
Na+ (g) + Cl- (g) → NaCl (s)  -787 kJ/mol
Chapter 9: Examples –
Formation of Ionic Compounds
9.2.   Calculate the energy released in kJ/mol when
sodium iodide is formed.
Na (s) + ½ I2 (s) → NaI (s)
The energy of vaporization of elemental
sodium is 107 kJ/mol. The ionization energy
of sodium is 486 kJ/mol. The sum of the
enthalpies of dissociation and vaporization of
elemental iodine is 214 kJ/mol and the
electron affinity of iodine is -295 kJ/mol. The
lattice energy of sodium iodide is -704 kJ/mol.
Chapter 9: Examples –
Formation of Ionic Compounds
9.3.   Calculate the energy released in kJ/mol when
lithium hydride is formed. The heat of
vaporization of elemental lithium is 161
kJ/mol, the ionization energy of lithium is 520
kJ/mol. The dissociation energy of hydrogen
gas is 436 kJ/mol and the electron affinity of a
gaseous hydrogen atom is -73 kJ/mol. The
lattice energy of lithium hydride is -917
kJ/mol.
Chapter 9: Examples –
Formation of Ionic Compounds
9.4.   Determine the energy of formation of
magnesium bromide. Given:
Mg (s) → Mg (g)                  +147.7 kJ/mol
Mg (g) → Mg+(g) + 1 e-           +737.7 kJ/mol
Mg+(g) → Mg2+ (g) + 1 e-         +1,450.7 kJ/mol
Br2 (g) → 2 Br (g)               +193 kJ/mol
Br (g) + 1 e- → Br- (g)          -325 kJ/mol
Mg2+ (g) + 2 Br- (g) → MgBr2 (s) -2,440 kJ/mol
Bond Polarity

NaCl      HCl          Cl-Cl
Bond length - the optimum distance
between nuclei in a covalent bond.
Metal Bonding

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