160 likes | 352 Views
Ionic Bonds. 08/29 & 08/30. Catalyst. Complete the Chart. Objectives. I can explain how electrons are transferred in an ionic bond. I can explain that ionic compounds form crystals. I can use the octet rule and the Criss Cross rule to predict how ionic bonds will form. Think Box:.
E N D
Ionic Bonds 08/29 & 08/30
Catalyst • Complete the Chart
Objectives • I can explain how electrons are transferred in an ionic bond. • I can explain that ionic compounds form crystals. • I can use the octet rule and the Criss Cross rule to predict how ionic bonds will form.
Think Box: • Look at your chart above. Do metals form anions or cations? Do nonmetals form anions or cations? • Answer: Metals form positive cations. Nonmetals for negative anions.
Notes: What is an ionic compound? • An ionic bond is the electrostatic attraction betweenoppositely charged ions. eg. Na+ and Cl-
Notes: What is an ionic compound? • Ionic compounds form when electrons are transferredfrom a metalcationto a non-metal anion.
Notes: What is an ionic compound? • Anionic compoundis made up of a metal and a non-metal. Lithium + Hydrogen Lithium Hydride Aluminum + Oxygen Aluminum Oxide Sodium + Chlorine Sodium Chloride
Ionic compounds form acrystal lattice structure. Silver + Bromine Silver Bromide Magnesium + Tellurium Magnesium Telluride Sodium + Chlorine Sodium Chloride
Even though ions have a charge, ionic compounds are neutral overall. Examples Na+ + Cl− → NaCl Li+ + H− → LiH Ca2+ + F- → CaF2 Al3+ + O2- → Al2O3
Ionic compound names: list the metal first, then the nonmetal. Change the last syllable of the nonmetal to –ide. If the metal forms more than one cation (transition metals) indicate the ion formed with a roman numeral. Examples Na+ + Cl− → NaCl Sodium Chloride Li+ + H− → LiH Lithium Hydride Ca2+ + F- → CaF2 Calcium Fluoride Al3+ + O2- → Al2O3 Aluminum Oxide Ag2++ O2- → AgO Silver (II) Oxide
Think Pair Share • If ionic compounds are really large collections of ions in a crystal lattice structure, why do we write equations and chemical formulas showing just a few ions? Examples Na+ + Cl− → NaCl Li+ + H− → LiH Ca2+ + F- → CaF2 Al3+ + O2- → Al2O3
Compound formulas show the proportion of cations to anions in an ionic compound. • The proportion is based on an overall neutral compound. • Use the Kris-Cross rule to find the correct proportion.
Ca2+As3- Kris Kross Method! Ca3As2
Just kris kross the positive and the negative charges Na1+Cl1- NaCl Pb4+O2- Pb2O4
Writing Compound Formulas Example Calcium and Fluorine Step 1: Use the octet rule to write the ions separately. Step 2: Kris-Cross the charge to make subscripts. Ca2+ F- CaF2 The subscripts shows the proportion of cations to anions. Here, it is 1:2.
Ionic Bonding Practice • List the original ions, the chemical formula for the compound formed (with the correct proportions of ions for an overall neutral charge), and the compound name. 1. Sodium and Chlorine Na+ Cl- NaCl Sodium Chloride