Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Notes Chap 5: This chapter is the key to the rest of the year in chemistry. A good level of mastery is essential. Joke: Two hydrogen atoms walk into a Starbucks. One of them says to the other, “Hey, I think I lost an electron.” The other one says, “Are you sure?” The first one answers, “I’m positive.”

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Two column notes Ion - an atom or molecule that has gained or lost electrons and has a negative or positive charge. Octet Rule (Rule of 8) - Tendency to have either empty outer energy levels or full outer energy levels of eight electrons.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu A Cation is… l A positive ion. l Formed by losing electrons. l More protons than electrons. l Metals can lose electrons K 1+ Has lost one electron Ca 2+ Has lost two electrons

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu An Anion is… A negative ion. Has gained electrons. Nonmetals can gain electrons. Charge is written as a superscript on the right. F 1- Has gained one electron O 2- Gained two electrons (oxide)

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What the book doesn’t teach, yet is essential for future success in Chem: •States of matter of the elements: Hg and Br are the liquids. H, O, N, Cl, F, and the noble gases (group 18) are gases.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu DIATOMIC ELEMENTS The diatomic elements (exist naturally in pairs) are essential to memorize for future use. H,O,N and the halogens (group 17).

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Page 162 Figure 5 This is something to memorize for the quiz with diatomics, polyatomics

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Some Ions with Noble-Gas Configurations Chapter 5 Section 1 Simple Ions

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Some Stable Ions Do Not Have Noble-Gas Configurations Section 1 Simple Ions Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Stable Ions Formed by the Transition Elements and Some Other Metals Chapter 5 Section 1 Simple Ions

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atoms and Ions Both sodium and chlorine are very reactive. When they are mixed, a violent reaction takes place, producing a white solid—table salt (sodium chloride). It is made from sodium cations and chloride anions. Ions and Their Parent Atoms Have Different Properties Section 1 Simple Ions Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atoms and Ions, continued Atoms of Metals and Nonmetal Elements Form Ions Differently Nearly all metals form cations. For example, magnesium metal, Mg, has the electron configuration: [Mg] = 1s 2 2s 2 2p 6 3s 2 ? - gain 6 electrons or lose 2. Losing 2 electrons requires less energy than gaining 6. Section 1 Simple Ions Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Atoms and Ions, continued Atoms of Metals and Nonmetal Elements Form Ions Differently, continued The atoms of all nonmetal elements form anions. For example, oxygen, O, has the electron configuration: [O] = 1s 2 2s 2 2p 4 To have a noble-gas configuration, an oxygen atom must either gain two electrons or lose six. Acquiring two electrons requires less energy than losing six. Section 1 Simple Ions Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Bonding Ionic Bonds form between ions of opposite charge. Section 2 Ionic Bonding and Salts Chapter 5 Ionic compounds consist of a combination of cations and an anions.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Demonstration: 1.Attraction force between opposite charge ions 2.Magnesium reactivity With water With Hydrochloric acid With oxygen

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic compound Properties: Opposite charges attract - Electrostatic attraction Very strong High Melting and Boiling Point All are Solid in room temperature Electric current Hard and Brittle Crystal lattice – repeat unit (arrangement)

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Compounds, continued Ionic Compounds Have Distinctive Properties, continued Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Compounds, continued Salts Are Hard and Brittle Like NaCl, most ionic compounds are hard and brittle. Hard means that the crystal is able to resist a large force applied to it. Brittle means that when the applied force becomes too strong to resist, the crystal develops a widespread fracture rather than a small dent. Both properties are due to the patterns in which the cations and anions are arranged in all salt crystals. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Bonding All salts are electrically neutral ionic compounds. However, the attractions between the ions in a salt do not stop with a single cation and a single anion. One cation attracts several anions, and one anion attracts several cations. They are all pulled together into a tightly packed crystal structure. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The ionic compound NaCl

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Bonding Transferring Electrons Involves Energy Changes Ionization energy is the energy that it takes to remove the outermost electron from an atom. The equation below shows this process for sodium. Na + energy  Na + + e  With some elements, such as chlorine, energy is released when an electron is added. Cl + e   Cl  + energy Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Salt Formation Involves Endothermic Steps The process of forming the salt sodium chloride can be broken down into five steps. 1.Energy is needed to make solid sodium a gas. Na(solid) + energy  Na(gas) 2.Energy is also required to remove an electron from a gaseous sodium atom. Na(gas) + energy  Na + (gas) + e  Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Salt Formation Involves Endothermic Steps 3.Chlorine - a diatomic element. Energy must be supplied to separate the chlorine atoms so that they can react with sodium. Cl–Cl(gas) + energy  Cl(gas) + Cl(gas) To this point, the first three steps have all been endothermic. These steps have produced sodium cations and chlorine atoms. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formation of Sodium Chloride Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Salt Formation Also Involves Exothermic Steps 4.An electron is added to a chlorine atom to form an anion. This step releases energy. Cl(gas) + e   Cl  (gas) + energy 5.When a cation and anion form an ionic bond, it is an exothermic process. Energy is released. Na + (gas) + Cl  (gas)  NaCl(solid) + energy The last step is the driving force for salt formation. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Salt Formation Also Involves Exothermic Steps The energy released when ionic bonds are formed is called the lattice energy. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ionic Compounds Do Not Consist of Molecules The ratio of cations to anions is always such that an ionic compound has no overall charge. Ionic Compounds Water is a molecular compound, so individual water molecules are each made of two hydrogen atoms and one oxygen atom. Sodium chloride is an ionic compound, so it is made up of many Na + and Cl  ions all bonded together to form a crystal. There are no NaCl molecules. Section 2 Ionic Bonding and Salts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer Put the following names in the correct order: Einstein Albert Marie Madame Curie Carver Washington George Cations and anoins can be thought of as the first and last names, respectively, of ionic compounds. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Name cations, anions, and ionic compounds. Write chemical formulas for ionic compounds such that an overall neutral charge is maintained. Explain how polyatomic ions and their salts are named and how their formulas relate to their names. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Naming Ionic Compounds Salts that are made of a simple cation and a simple anion are known as binary ionic compounds. The adjective binary indicates that the compound is made up of just two elements. Rules for Naming Simple Ions Simple cations borrow their names from the names of the elements. For example, K + is known as the potassium ion. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Naming Ionic Compounds When an element forms two or more ions, the ion names include roman numerals to indicate charge. For example, the names of the two copper ions are: Cu + copper(I) ionCu 2+ copper(II) ion Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Naming Ionic Compounds, continued The name of a binary ionic compound is made up of just two words: the name of the cation followed by the name of the anion. Anoin’s end changes –ide-. NaCl sodium chlorideCuCl 2 copper(II) chloride ZnS zinc sulfideMg 3 N 2 magnesium nitride K 2 O potassium oxideAl 2 S 3 aluminum sulfide Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Writing Ionic Formulas Ionic compounds have a balance of positive and negative charges. Section 3 Names and Formulas of Ionic Compounds Chapter 5 In some ionic compounds, the charges of the cation and anion differ. For example, in magnesium nitride, the Mg 2+ ion, has two positive charges, and the N 3  ion, has three negative charges.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Writing Ionic Formulas Three Mg 2+ cations are needed for every two N 3  anions for electroneutrality. That way, there are six positive charges and six negative charges. Subscripts are used to denote ion ratios. Therefore, the formula for magnesium nitride is Mg 3 N 2. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Polyatomic Ions Many Atoms Can Form One Ion A simple ion is monatomic, which means “one-atom.” A polyatomic ion is a charged group of two or more bonded atoms that can be considered a single ion. Unlike simple ions, most polyatomic ions are made of atoms of several elements. Like simple ions, polyatomic ions either positive or negative charge. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Polyatomic Ions Many Atoms Can Form One Ion Consider the polyatomic ion ammonium, NH 4 +. Ammonium is made of one nitrogen and four hydrogen atoms. They have a total of 11 protons but only 10 electrons. So the ammonium ion has a 1+ charge overall. Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Comparing Monatomic, Diatomic, and Polyatomic Structures Visual Concepts Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Polyatomic Ions, continued The Names of Polyatomic Ions Can Be Complicated The endings -ite and -ate in the name for a polyatomic indicate the presence of oxygen and the number of oxygen atoms present. For example, the formulas for two polyatomic ions made from sulfur and oxygen are Section 3 Names and Formulas of Ionic Compounds Chapter 5 and. The one with less oxygen takes the -ite ending, so is named sulfite. The ion with more oxygen takes the -ate ending, so is named sulfate.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formula of a Compound with a Polyatomic Ion Sample Problem A What is the formula for iron(III) chromate? Section 3 Names and Formulas of Ionic Compounds Chapter 5

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formula of a Compound with a Polyatomic Ion, continued Sample Problem A Solution Section 3 Names and Formulas of Ionic Compounds Chapter 5 Determine the formula and charge for the iron(III) cation. Fe 3+ Determine the formula and charge for the chromate polyatomic ion.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formula of a Compound with a Polyatomic Ion, continued Because ionic compounds are electrically neutral, the total charges of the cations and anions must be equal. To balance the charges, find the least common multiple of the ions’ charges: for 2 and 3, it is 6. For 6 positive charges, you need 2 Fe 3+ ions. 2  3 = 6+ Section 3 Names and Formulas of Ionic Compounds Chapter 5 Sample Problem A Solution, continued

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Formula of a Compound with a Polyatomic Ion, continued Sample Problem A Solution, continued Section 3 Names and Formulas of Ionic Compounds Chapter 5 3  2 = 6  The formula must show 2 Fe 3+ ions and 3 ions. Parentheses are used whenever a polyatomic ion is present more than once. The formula for iron(III) chromate is Fe 2 (CrO 4 ) 3. For 6 negative charges, you need 3 ions.