Fun with Chemistry

Chapter 15 Ionic Bonding and Ionic Compounds

15.1 Electron Configuration in Ionic Bonding

• Valence Electrons
o Electrons in the highest occupied energy level of an element’s atoms
• Representative elements have the same number of valence electrons as their group numbers
• Usually the only electrons used in bonding
• Exceptions are some transition metals
o Electron dot structures
• Illustrate only the valence electrons
• Electron Configuration for Cations
o Octet rule
• In forming compounds, atoms tend to achieve the electron configuration of a noble gas
• Eight electrons in the outermost energy level
o Metallic elements tend to lose electrons to form this configuration
• Form the noble gas configuration of the noble gas in the previous period
• Some transition metals tend to take the configuration in which 18 electrons are in the highest energy level instead of 8
• Electron Configuration for Anions
o Nonmetals that form a negative charge by gaining electrons
• Form the noble gas configuration of the noble gas in the same period

15.2 Ionic Bonds

• Ionic Bonds
o Electrostatic forces that draw anions and cations together
o Combine to form ionic compounds
• Metal will lose its electrons
• Nonmetals will gain the electrons
• Properties of Ionic Compounds
o Most ionic compounds form crystalline solids
• Crystalline structure is the reason that ionic compounds have such a high melting point
o Coordination number
• Indicates the number of oppositely charged ions that surround an ion
o Structures of ionic compound are founded using a method called x ray diffraction crystallography
o When melted, ionic compounds conduct electric current
• Also conduct electric current when dissolved in water

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