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Types of Compounds 2 Types of Compounds Ionic Covalent Contrasting Ionic and Covalent Compounds Covalent Ionic Result from sharing e Result from a transfer in e Metal & a nonmetal 2 nonmetals Strong crystal structure Interpartical F is weak Solid at room temp liquid or gas High melt pt Low melt pt Dissolve in water Less soluble in water Electrolytes Poor conductors of electricity I. Ionic Compoundscompounds composed of ions 1. 2. Ionic bonds- attractive F between ions of opp. charge Result from a transfer of e- Na [Na]+ Cl [Cl]- A. Binary Compounds- a compound that contains only 2 elements To name a binary compound 1. 2. 3. Write the name of the + charged ion (metal) Add the name of the – charged ion (nonmetal) Change the end of the name of the nonmetal to “ide” Examples NaCl Sodium Chlorine ide You try it! Name MgO magnesium oxide B. Formula- in ionic compounds, the smallest ratio of atoms or ions in the compound 1. formula unit – simplest ratio of ions in a compound Example: How many formula units of each are present? 2NaCl 3NaCl NaCl C. Predicting charges 1. 2. 3. 4. Metals lose e-, so they form positive ions. Nonmetals gain e-, so they form negative ions. Charge = oxidation # Oxidation # is used to determine formulas. D. Writing formulas 1. aluminum + oxygen = Aluminum has 3 valence, so it gives away 3 e- Oxygen has 6 valence, so it accepts 2 e- Al3+ + O2- Al2O3 The oxidation numbers must add up to zero. If not you have to multiply to make them. Practice Problems E. Polyatomic ion- ion that has 2 or more different elements 1. 2. 3. 4. A group of atoms is covalently bonded together The individual atoms have no charge, but the group as a whole does See page 109 & handout Quiz tomorrow on the 1st 9 polyatomic ions on the chart 5. Compounds containing P.I. Positive metal ions bond to negative P.I. ions + OH- = NaOH Negative nonmetal ions bond to Positive P.I. Ex: Na+ Ex: NH4+ I- = + NH4I Positive P.I. can bond with Negative P.I. Ex: NH4+ + OH- = NH4OH 6. If you have to multiply P.I., use parentheses Examples: (NH4)2 Mg2+ or (H3O)3 + NO3- = Mg(NO3)2 7. To name compounds containing P.I. Name the + ion first, followed by the – ion. Never change the name of a polyatomic ion!!!! Example CaCO3 = calcium carbonate Practice Problems Do a-d & f on Practice Problem Exercise 4.7 on pg 111 omit e & f. F. Transition metals 1. 2. Transition metals can have more than 1 oxidation #. ex: Copper can be Cu+ or Cu2+ ex: Fe can be Fe2+ or Fe3+ Exceptions a. Zn has a +2 charge b. Ag has a +1 c. Cd has a +2 Transition metals cont. 3. 4. A Roman numeral is put in parentheses after the name of the transition element to show its oxidation #. Example: Cu+ Cu2+ + Cl+ Cl- CuCl = copper(I) chloride CuCl2 = copper(II) chloride Practice Problems p 102 II. Molecular Substances (covalent compounds) Covalent bonds-form when e- are shared 1. Covalent compound- compound held together by covalent bonds 2. Molecule- 2 or more atoms held together by covalent bonds B. Ionic & Covalent Compounds can be Separated 1. Distillation- separation method that uses evaporation & condensation of a liquid http://www.ktf-split.hr/glossary/en_o.php?def=distillation C. Molecular element- form when atoms of the same element bond example: O2, N2, H2, F2, Cl2 D. Allotropes- combinations of a single element that differ in structure Example: O2 is oxygen gas O3 is ozone E. Formulas & Names 1. 2. 3. Write out the name of the 1st nonmetal, followed by the 2nd nonmetal with “ide” for an ending. 1st element is farther to the left on periodic table. If both are in the same group, the one closest to the bottom goes 1st. Formulas & Names Cont. 4. Put a prefix on the name of each element to show the # of atoms present. Example: C2O = dicarbon monoxide C3O5 = tricarbon pentoxide 5. Exceptions a. If only 1 atom of 1st element present, leave off “mono” Example: NO6 = nitrogen hexoxide b. If o-o or a-o appear, leave off the 1st vowel. F. Common Names (p182) Some substances are known by their common name more than their proper name. Examples: 1. What is the proper name of H2O? HCl = hydrochloric acid H2SO4 = sulfuric acid H3PO4 = phosphoric acid HC2H3O2 = acetic acid NH3 = ammonia 2. Organic compounds a. Hydrocarbon – compounds that contain H and C only Examples: CH4 = methane C2H6 = ethane C3H8 = propane C4H10 = butane Test!!!!!!!