1 Chapter 6 Inorganic and Organic Compounds: Names and Formulas 6.5 Covalent Compounds and Their Names Basic Chemistry Copyright © 2011 Pearson Education, Inc.

2 Forming a H 2 Molecule Basic Chemistry Copyright © 2011 Pearson Education, Inc. A covalent bond forms as H atoms move close together to share electrons.

3 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) Basic Chemistry Copyright © 2011 Pearson Education, Inc.

4 Diatomic Elements These elements share electrons to form diatomic, covalent molecules. Basic Chemistry Copyright © 2011 Pearson Education, Inc.

5 What is the name of each of the following diatomic molecules? H 2______________________ N 2 _______________ Cl 2 _______________ O 2 _______________ I 2 _______________ Learning Check Basic Chemistry Copyright © 2011 Pearson Education, Inc.

6 What are the names of each of the following diatomic molecules? H 2 hydrogen N 2 nitrogen Cl 2 chlorine O 2 oxygen I 2 iodine Solution Basic Chemistry Copyright © 2011 Pearson Education, Inc.

7 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 Basic Chemistry Copyright © 2011 Pearson Education, Inc.

8 Electron-Dot Formulas and Models of Some Covalent Compounds Basic Chemistry Copyright © 2011 Pearson Education, Inc.

9 Names of Covalent Compounds Prefixes are used in the names of covalent compounds because two nonmetals can form two or more different compounds Examples of compounds of N and O: NO nitrogen oxide NO 2 nitrogen dioxide N 2 O dinitrogen oxide N 2 O 4 dinitrogen tetroxide N 2 O 5 dinitrogen pentoxide Basic Chemistry Copyright © 2011 Pearson Education, Inc.

10 Guide to Naming Covalent Compounds Basic Chemistry Copyright © 2011 Pearson Education, Inc.

11 To name the covalent compound SO 3, STEP 1 Name the first nonmetal by its element name. The element S is sulfur. STEP 2 Name the second nonmetal by using the first syllable of its element name followed by ide. O is named oxide. STEP 3 Add prefixes to indicate the number of atoms (subscripts). The subscript 3 of O is shown as the prefix tri. SO 3 → sulfur trioxide The subscript 1(for S) or mono is understood. Naming Covalent Compounds Basic Chemistry Copyright © 2011 Pearson Education, Inc.

12 What is the name of P 4 S 3 ? STEP 1 Name the first nonmetal by its element name. P is named phosphorus. STEP 2 Name the second nonmetal by using the first syllable of its element name followed by ide. S is named sulfide. STEP 3 Add prefixes to indicate the number of atoms (subscripts). The subscript 4 of P is written as tetra. The subscript 3 of O is written as tri. P 4 S 3 → tetraphosphorus trisulfide Naming Covalent Compounds Basic Chemistry Copyright © 2011 Pearson Education, Inc.

13 Formulas and Names of Some Covalent Compounds Basic Chemistry Copyright © 2011 Pearson Education, Inc.

14 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 Learning Check Basic Chemistry Copyright © 2011 Pearson Education, Inc.

15 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 Solution Basic Chemistry Copyright © 2011 Pearson Education, Inc.

16 Write the name of each covalent compound: CO_____________________ CO 2 _____________________ PCl 3 _____________________ CCl 4 _____________________ N 2 O_____________________ Learning Check Basic Chemistry Copyright © 2011 Pearson Education, Inc.

17 Write the name of each covalent compound: CO carbon monoxide CO 2 carbon dioxide PCl 3 phosphorus trichloride CCl 4 carbon tetrachloride N 2 Odinitrogen oxide Solution Basic Chemistry Copyright © 2011 Pearson Education, Inc.

18 Example: Write the formula for carbon disulfide. STEP 1 Write the symbols in the order of the elements in the name. C S STEP 2 Write any prefixes as subscripts. No prefix for carbon means one(1) C. The prefix di for sulfur means two(2) S. formula: CS 2 Guide to Writing Formulas Basic Chemistry Copyright © 2011 Pearson Education, Inc.

19 Write the correct formula for each of the following: A. phosphorus pentachloride B. dinitrogen trioxide C. sulfur hexafluoride Learning Check Basic Chemistry Copyright © 2011 Pearson Education, Inc.

20 Write the correct formula for each of the following: A. phosphorus pentachloride 1 P penta = 5 ClPCl 5 B. dinitrogen trioxide di = 2 N tri = 3 ON 2 O 3 C. sulfur hexafluoride 1 S hexa = 6 FSF 6 Solution Basic Chemistry Copyright © 2011 Pearson Education, Inc.

21 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 Basic Chemistry Copyright © 2011 Pearson Education, Inc.

22 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 Basic Chemistry Copyright © 2011 Pearson Education, Inc.

23 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 Basic Chemistry Copyright © 2011 Pearson Education, Inc.

24 Solution A. Ca 3 (PO 4 ) 2 ionic Ca 2+ PO 4 3− calcium phosphate B. FeBr 3 ionic Fe 3+ Br − iron(III) bromide C. SCl 2 covalent 1S 2Cl sulfur dichloride D. Cl 2 O covalent 2Cl 1O dichlorine oxide Basic Chemistry Copyright © 2011 Pearson Education, Inc.