Ionic Bonds Chemistry Mrs. Coyle Part A: Ions Lewis Dot Structure Stable Octet (or Duet) The Periodic Table and Atomic Radius Valence Electrons Valence electrons are the electrons in the highest occupied energy level of the atom. Valence electrons are the only electrons generally involved in bond formation. Electron Configuration of Sodium 1s2 2s2 2p6 3s1 Which is the valence electron for Na? Answer: 1s2 2s2 2p6 3s1 Na , 11 e Na + , 10e A Positive Ion (Cation): An atom that has lost one or more electrons. + charge Electron Dot Structure or Lewis Dot Diagram A notation showing the valence electrons surrounding the atomic symbol. Elements within the same group have the same electron-dot structure. A Negative Ion (Anion) An atom that has gained one or more electrons. Negatively (-) charged. Chlorine Atom Chlorine Ion Check your Neighbor When Na, (Z= 11) loses its valence electron, what element does its configuration look like ? a. b. c. d. Neon Potassium Beryllium Sodium Check your Neighbor When Na, (Z= 11) loses its valence electron, what element does its configuration look like ? a. b. c. d. Neon Potassium Beryllium Sodium A Stable Octet When the valence shell is full, the atom is stable, less likely to react. Example: Noble (Inert Gases) Kr Note Atoms tend to react in a way that would lead them to have a stable octet. Part B: Equations for Formation of Ions and Naming Ions Ionic Bonds and Ionic Compounds Equations for the Formation of Cations . H H+ + e- . Li Li+ + e- Mg: Mg2+ + 2e- Equations for the Formation of Anions . :F: .. .. + e- : F - .. : Naming cations (+). Use the name of the metal. Example: Na+ Sodium ion. Naming Anions(-) Use the name of the nonmetal with the ending –ide. Example: F Fluoride Ionic Compounds Are made up of: a metal and a nonmetal ion. polyatomic ions. Naming Ionic Compounds, a First Look Example: NaF Sodium Fluoride Example: Which of the following compounds are ionic? 1. 2. 3. 4. 5. NaCl CO2 CO KF KNO3 Some Common Ions Bonding Elements that do not have a complete octet, tend to react. When the elements react bonds are formed. Types of Bonds Ionic Metallic Covalent Ionic Bonds Bonds that are formed by transfer of electrons from one element to the other. Each element (now an ion) will have a complete octet after the transfer of electrons. The Ionic Bond • The electrical force of attraction between oppositely charged ions. Na+ F− Example: Formation of Lithium Fluoride . . Li + :F: .. .. Li+ : F- .. : Is an Ionic Compound Electrically Neutral or Charged? Movie Clip http://www.youtube.com/watch?v=Kj3o0XvhV qQ&NR=1 Chemical Formula A representation of the kinds and number of atoms in a substance. Formula Unit A chemical formula that shows the lowest whole number ratio of the atoms (ions) in an ionic compound. Example: KCl, Mg Cl2 The formula unit is used because ionic compounds have a lattice arrangement of ions. Ex: NaCl Which ball represents the Na?