Ionic Compounds Chapter 8 I will define a chemical bond I will describe how ions form I will identify ionic bonding and the characteristics of ionic compounds I will name and write chemical formulas for ionic compounds I will relate metallic bonds to the characteristics of metals

Forming Chemical Bonds I will define chemical bond I will relate chemical bond formation to electron configuration I will describe the formation of positive and negative ions Vocabulary: chemical bond, cation, anion

Chemical Bond A force that holds two atoms together Form in two ways: By the attraction between a positive nucleus and negative electrons By the attraction between a positive ion and a negative ion Recall: Valence electrons are involved in the formation of chemical bonds between 2 atoms Atoms want 8 valence electrons so they have a stable electron structure (helium only needs 2)

Positive ions form when an atom loses one or more valence electrons in order to attain a full outer shell Formation of Positive Ions Cation A positively charged ion atom + ionization energy = ion + + electron(s)

Which Elements Form Positive Ions? Group 1A Lose 1 electron Form +1 ions Group 2A Lose 2 electrons Form +2 ions Transition Metals (DIFFICULT to predict) Outer energy level ns 2 (in general) L  R atoms of each element are also filling in the d sublevel Commonly lose their 2 valence electrons (form+2 ions) Also possible for d electrons to be lost Allows them to form +3 ions or greater Group 3A (a few) Lose 3 electrons Form +3 ions

Negative ions form when an atom gains one or more valence electrons in order to attain a full outer shell Formation of Negative Ions Anion A negatively charged ion atom + electron(s) = ion -- + electron affinity

Which Elements Form Negative Ions? To designate an anion, the ending –ide is added to the root name of the element Ex NaCl = sodium chloride Some nonmetals can gain or lose other numbers of electrons to form an octet Ex phosphorous Gain 3 electrons Or Lose 5 electrons MORE LIKELY to GAIN 3!! Nonmetals Gain the number of electrons that when added to their valence electrons, equals 8 The number of electrons gained corresponds to their negative charge Ex gain 2 electrons = form --2 ions

The Formation and Nature of Ionic Bonds I will describe the formation of ionic bonds I will account for many of the physical properties of an ionic compound I will discuss the energy involved in the formation of an ionic bond Vocabulary: ionic bond, electrolyte, lattice energy

Names and Formulas for Ionic Compounds I will write formulas for ionic compounds and oxyanions I will name ionic compounds and oxyanions Vocabulary: formula unit, monatomic ion, oxidation number, polyatomic ion, oxyanion

Metallic Bonds and Properties of Metals I will describe a metallic bond I will explain the physical properties of metals in terms of metallic bonds I will define and describe alloys Vocabulary: electron sea model, delocalized electrons, metallic bond, alloy