5.5 Covalent Compounds and Their Names. Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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1 5.5 Covalent Compounds and Their Names Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 1

2 I. Molecular Nomenclature A. There are two ways to name: The stock system which uses oxidation numbers and the older more popular Prefix System. 1. Molecules are made of covalently bonded atoms! 2. These chemical formulas do not need reduced or simplified in the end

3 B. Prefix System (binary) 1. Less e - neg atom comes first. 2. Add prefixes to indicate # of atoms. Omit mono- prefix on first element. 3. Change the ending of the second element to -ide.

4 C. Prefixes PREFIX monoditritetrapentahexaheptaoctanonadeca- NUMBER

5 Examples: Name These CCl 4 carbon tetrachloride N 2 O dinitrogen monoxide SF 6 sulfur hexafluoride

6 arsenic trichloride AsCl 3 dinitrogen pentoxide N 2 O 5 More Examples: Write out these formulas tetraphosphorus decoxide P 4 O 10

7 C. Molecular Nomenclature The Seven Diatomic Elements Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2 H N O F Cl Br I

8 8

9 Forming a H 2 Molecule 9 Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

10 H 2, A Covalent Molecule In a hydrogen (H 2 ) molecule Two hydrogen atoms share electrons to form a covalent single bond. Each H atom acquires two (2) electrons. Each H becomes stable like helium (He). Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 10

11 Learning Check What is the name of each of the following diatomic molecules? H 2 N 2 Cl 2 O 2 I 2 11

12 Formulas and Names of Some Covalent Compounds TABLE 4.13 Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 12

13 Learning Check Select the correct name for each compound. A. SiCl 4 1) silicon chloride 2) tetrasilicon chloride 3) silicon tetrachloride B. P 2 O 5 1) phosphorus oxide 2) phosphorus pentoxide 3) diphosphorus pentoxide C. Cl 2 O 7 1) dichlorine heptoxide 2) dichlorine oxide 3) chlorine heptoxide 13

14 Solution Select the correct name for each compound. A. SiCl 4 3) silicon tetrachloride B. P 2 O 5 3) diphosphorus pentoxide C. Cl 2 O 7 1) dichlorine heptoxide 14

15 Learning Check Write the name of each covalent compound: CO CO 2 PCl 3 CCl 4 N 2 O 15

16 Solution Write the name of each covalent compound: CO CO 2 PCl 3 CCl 4 N 2 O carbon monoxide carbon dioxide phosphorus trichloride carbon tetrachloride dinitrogen oxide 16

17 Learning Check Write the correct formula for each of the following: A. phosphorus pentachloride B. dinitrogen trioxide C. sulfur hexafluoride 17

18 Solution Write the correct formula for each of the following: A. phosphorus pentachloride 1 P penta = 5 Cl PCl 5 B. dinitrogen trioxide di = 2 N tri = 3 O N 2 O 3 C. sulfur hexafluoride 1 S hexa = 6 F SF 6 18

19 Learning Check Identify each compound as ionic or covalent and give its correct name. A. SO 3 B. MnCl 2 C. (NH 4 ) 3 PO 4 D. Cu 2 CO 3 E. N 2 O 4 19

20 Solution Identify each compound as ionic or covalent and give its correct name. A. SO 3 covalent - sulfur trioxide B. MnCl 2 ionic - manganese(ii) chloride C. (NH 4 ) 3 PO 3 ionic - ammonium phosphite D. Cu 2 CO 3 ionic copper(i) carbonate E. N 2 O 4 covalent dinitrogen tetroxide 20

21 Learning Check Identify each compound as ionic or covalent and give its correct name. A. Ca 3 (PO 4 ) 2 B. FeBr 3 C. SCl 2 D. Cl 2 O 21

22 Solution A. Ca 3 (PO 4 ) 2 ionic Ca 2+ PO 3 4 calcium phosphate B. FeBr 3 ionic Fe 3+ Br iron(iii) bromide C. SCl 2 covalent 1S 2 Cl D. Cl 2 O covalent 2 Cl 1 O sulfur dichloride dichlorine oxide 22

23 Electron-Dot Formulas Electron-dot formulas show The order of bonded atoms in a covalent compound. The bonding pairs of electrons between atoms. The unshared (lone) valence electrons. A central atom with an octet. Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 23

24 Electron-Dot Formulas and Models of Some Covalent Compounds Table Copyright 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

25 Drag and Drop practice aters/ions/page1.htm Balloon Molecules ung_vor.htm Balancing Ions Naming Practice Sites ormulas.html