Ionic Bonding Kari Rogers and Emily Rankin

Forming ionic bonds are usually exothermic reactions If the charge is positive, an electron has been lost If the charge is negative, an electron has been gained Electron transfers occur when atoms involved differ in the attraction for electrons

“NaCl is typical ionic compound because it consists of a metal of low ionization energy and a nonmetal with high affinity for electrons” (pg. 278)

Lewis electron dot symbols Arrow = transfer of Na electron to the Cl atom Each ion has an octet of electrons Octet = 8 electrons

Energies of ionic bond formation Ionic compounds are stable because the attraction between ions of unlike charges. This attraction makes the ions draw together, which then releases energy and forms the ions into a solid “array or lattice”

Lattice Energy “Energy required to completely separate a mole of a solid ionic compound into its gaseous ions” (page 278) Will always be positive “Energy released by attraction between ions of unlike charge makes up for the endothermic nature of ionization energies, making the formation of ionic compounds”

Transition Metal-Ions When you form an ion, transition metals lose the valence-shell, S electrons first, then as many D electrons that are required to reach the charge of the ion

Polyatomic Ions A group of atoms as a whole acts as a charged species in forming an ionic compound with an ion of the opposite charge

Born-Haber Cycle Thermochemical cycle that analyzes the factors that contribute to the stability of the ionic compounds Five Steps: 1. Generate gaseous atoms of Na by vaporizing Na metal 2. Form gaseous atoms of Cl by breaking the bonds of the Cl2 molecules 3 & 4: Remove the electron from Na to form Na+ and add the electron to Cl to form Cl- 5. Combine the gaseous Na and Cl ions to form solid NaCl

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