Chapter 7: Ionic and Metallic Bonding Section 2: Ionic Bonds and Ionic Compounds

Formation of Ionic Compounds Ionic Compounds –Composed of metal ________ and nonmetal _____________. Ex. NaCl → Na + + Cl - –Composed of _______, but electrically _____________. Total ________ charge = Total _________charge

Formation of Ionic Compounds Ionic Bond –Anions and cations attracted by ___________ ______________. –Example 1 Na _________ electron to Cl ________ and _______ ions result Ions are then attracted by their _____________ (+1 and -1)

Formation of Ionic Compounds Ionic Bond –Example 2 Aluminum- _____ valence electrons Bromine- _____ valence electrons (needs _____) Aluminum _________ electron to each of three bromine atoms ______ ion and ______ ions result –What is the ionic compound that results?

Formation of Ionic Bonds Chemical formula –________ and _________ of atoms in the smallest unit of a substance –NaCl, H 2 O, CH 4 Formula Unit –lowest _________ _________ _______ of ions in an ionic compound –NaCl – ratio of ___ Na + : ____Cl - –MgCl 2 – ratio of ___ Mg 2+ : ____ Cl - –AlBr 3 – ratio of ___ Al 3+ : ____ Br -

Formation of Ionic Compounds AlBr 3 Number of Aluminum ions when no number is shown, assume there is 1 ion Number of Bromide ions ____:____ ratio of Al 3+ ions to Br - ions

Practice Predict the formula units that would form from the following elements 1.Draw electron dot structures 2.Determine ions that would form 3.How many of each ion is needed to have equal + and – charges? a. Potassium and iodine b. Potassium and oxygen c. Aluminum and oxygen

Properties of Ionic Compounds Solid _________ at room temperature –Ions _________ to their neighbors –strong, ________ structure Very ________ melting points –NaCl has a melting point of 800°C

Properties of Ionic Compounds Coordination number –number of ions of _________ _______ that surround an ion –Coordination # of Na + : –Coordination # of Cl - :

Practice What is the coordination number of cesium in cesium chloride (CsCl)? Pink- Cs + Blue- Cl -

Properties of Ionic Compounds When placed in water –Crystal structure breaks down, ____ separate –Conduct an _________ __________ when melted or dissolved Electrical current applied to water –___________ move toward one electrode and ___________ to another –____________ conducted through the water by way of ions