Chapter 3 Atoms to Molecules

Section 3.4 Molecules and Ions Return to TOC Copyright © Cengage Learning. All rights reserved 2 Covalent Bonds  Bonds form between atoms by sharing electrons.  Resulting collection of atoms is called a molecule. Chemical Bonds

Section 3.4 Molecules and Ions Return to TOC Copyright © Cengage Learning. All rights reserved 3 Ionic Bonds  Bonds form due to force of attraction between oppositely charged ions.  Ion – atom or group of atoms that has a net positive or negative charge.  Cation – positive ion; lost electron(s).  Anion – negative ion; gained electron(s). Chemical Bonds

Section 3.6 Chemical Equations Return to TOC Copyright © Cengage Learning. All rights reserved 4 A representation of a chemical reaction: C 2 H 5 OH + 3O 2  2CO 2 + 3H 2 O reactantsproducts Reactants are only placed on the left side of the arrow, products are only placed on the right side of the arrow.

Section 3.6 Chemical Equations Return to TOC Copyright © Cengage Learning. All rights reserved 5 C 2 H 5 OH + 3O 2  2CO 2 + 3H 2 O The equation is balanced. All atoms present in the reactants are accounted for in the products. 1 mole of ethanol reacts with 3 moles of oxygen to produce 2 moles of carbon dioxide and 3 moles of water.

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 6 Binary Compounds  Composed of two elements  Ionic and covalent compounds included Binary Ionic Compounds  Metal—nonmetal Binary Covalent Compounds  Nonmetal—nonmetal Naming Compounds

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 7 1.The cation is always named first and the anion second. 2.A monatomic cation takes its name from the name of the parent element. 3.A monatomic anion is named by taking the root of the element name and adding –ide. Binary Ionic Compounds (Type I)

Section 3.7 Naming Simple Compounds Return to TOC

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 9 Examples: KClPotassium chloride MgBr 2 Magnesium bromide CaOCalcium oxide Binary Ionic Compounds (Type I)

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 10 Metals in these compounds form more than one type of positive charge. Charge on the metal ion must be specified. Roman numeral indicates the charge of the metal cation. Transition metal cations usually require a Roman numeral. Binary Ionic Compounds (Type II)

Section 3.7 Naming Simple Compounds Return to TOC

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 12 Examples: CuBrCopper(I) bromide FeSIron(II) sulfide PbO 2 Lead(IV) oxide Binary Ionic Compounds (Type II)

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 13 Must be memorized (see Table 3.5 on pg. 130 in text). Examples of compounds containing polyatomic ions: NaOHSodium hydroxide Mg(NO 3 ) 2 Magnesium nitrate (NH 4 ) 2 SO 4 Ammonium sulfate Polyatomic Ions

Section 3.7 Naming Simple Compounds Return to TOC

Section 3.7 Naming Simple Compounds Return to TOC

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 16 Formed between two nonmetals. 1.The first element in the formula is named first, using the full element name. 2.The second element is named as if it were an anion. 3.Prefixes are used to denote the numbers of atoms present. 4.The prefix mono- is never used for naming the first element. Binary Covalent Compounds (Type III)

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 17 Prefixes Used to Indicate Number in Chemical Names

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 18 Examples: CO 2 Carbon dioxide SF 6 Sulfur hexafluoride N 2 O 4 Dinitrogen tetroxide Binary Covalent Compounds (Type III)

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 19 Acids can be recognized by the hydrogen that appears first in the formula—HCl. Molecule with one or more H + ions attached to an anion. Acids

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 20 If the anion does not contain oxygen, the acid is named with the prefix hydro– and the suffix –ic. Examples: HClHydrochloric acid HCNHydrocyanic acid H 2 SHydrosulfuric acid Acids

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 21 If the anion does contain oxygen:  The suffix –ic is added to the root name if the anion name ends in –ate. Examples: HNO 3 Nitric acid H 2 SO 4 Sulfuric acid HC 2 H 3 O 2 Acetic acid Acids

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 22 If the anion does contain oxygen:  The suffix –ous is added to the root name if the anion name ends in –ite. Examples: HNO 2 Nitrous acid H 2 SO 3 Sulfurous acid HClO 2 Chlorous acid Acids

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 23 Flowchart for Naming Acids

Section 3.7 Naming Simple Compounds Return to TOC Copyright © Cengage Learning. All rights reserved 24 Exercise Which of the following compounds is named incorrectly? a) KNO 3 potassium nitrate b) TiO 2 titanium(II) oxide c) Sn(OH) 4 tin(IV) hydroxide d) PBr 5 phosphorus pentabromide e) CaCrO 4 calcium chromate