Chapter 6 Ionic Compounds Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings Silence cell phones and pagers.

An octet Contains 8 valence electrons. Is associated with the stability of the noble gases. Exception is He that is stable with 2 valence electrons (duet). valence electrons He 22 (Exception) Ne 2, 88 Ar 2, 8, 8 8 Kr 2, 8, 18, 88 Octet Rule

Review: Valence Electrons The valence electrons Are the electrons in the s and p sublevels in the highest energy level. Are related to the Group number of the element. Determine the chemical properties of the elements. Elements with similar properties have the same number of ___________________ !

Forming Octets Atoms acquire octets By losing, gaining, or sharing valence electrons. To form compounds. To become more stable.

Size of Sodium Ion The sodium ion Na + Forms when the Na atom loses one electron from the 3 rd energy level, its valence electron. Is smaller than a Na atom. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings Octet

Size of Fluoride Ion The fluoride ion F - Forms when a valence electron is added. Has increased repulsions due to the added valence electron. Is larger than F atom Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings Octet

Ionic and Covalent Bonds Ionic bonds involve Loss of electrons by a metal. Gain of electrons by a nonmetal. Covalent bonds involve A sharing of electrons. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Metals Form Positive Ions Metals form Octets by losing all of their valence electrons. Positive ions with the electron configuration of the nearest noble gas. Positive ions with fewer electrons than protons. Group 1A(1) metals  ion 1+ Group 2A(2) metals  ion 2+ Group 3A(13) metals  ion 3+ Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Formation of a Sodium Ion, Na + Sodium achieves an octet by losing its one valence electron. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 2, 8, 1 2, 8

Charge of Sodium Ion, Na + With the loss of its valence electron, the sodium ion has a 1+ charge. Sodium atom Sodium ion 11p + 11p + 11e - 10e Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 2, 8

Formation of Mg 2+ Magnesium achieves an octet by losing its two valence electrons. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 2, 8, 2 2, 8

Charge of Magnesium Ion Mg 2+ With the loss of two valence electrons, magnesium forms a positive ion with a 2+ charge. Mg atomMg 2+ ion 12p + 12p + 12e- 10e Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 2, 8

Formation of Negative Ions In ionic compounds, nonmetals Achieve an octet arrangement. Gain electrons. Form negatively charged ions with 3-, 2-, or 1- charges.

Formation of Chloride Ion, Cl - Chlorine achieves an octet by adding an electron to its valence electrons. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings 2, 8, 7 2, 8, 8

Charge of a Chloride Ion, Cl - A chlorine ion forms When Cl gains one electron With a 1- charge. Chlorine atom Chloride ion 17p + 17p + 17e - 18e – Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Some Ionic Charges Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings I-I-

Ionic Charge from Group Numbers The charge of a positive ion is equal to its Group number. Group 1A(1) = 1+ Group 2A(2) = 2+ Group 3A(13) = 3+ The charge of a negative ion is obtained by subtracting 8 or 18 from its Group number. Group 6A(16) = = 2- or = 2-

Upon loss or gain of electons, the electronic arrangement of the ion is “_____________” with its nearest noble gas.

An octet Is ___ valence electrons Is associated with the stability of the noble gases He is stable with ___ valence electrons (duet). valence electrons He 1s 2 __ Ne 1s 2 2s 2 2p 6 __ Ar 1s 2 2s 2 2p 6 3s 2 3p 6 __ Kr 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 __ Octet Rule - What is special about “8” ?

Learning Check Select the correct answer for Sodium 1A(1): 1. Number of ________________ A) ________ B) ________ C) ________ 2. Electron ________ to achieve ________ A) ________ B) ________ C) ________ 3. _____________ of sodium ion A) ________ B) ________ C) ________ 4. The ________ for the sodium ion A) ________ B) ________ C) ________

Select the correct answer for nitrogen 5A(15): 5. Number of __________________ A) ________ B) ________ C) ________ 6.Change in ________ for ________ A) ________ B) ________ C) ________ 7. Ionic ________ of ________ A) ________ B) ________ C) ________ 8. The ________ for the ________ A) ________ B) ________ C) ________ Learning Check

Compounds - Compounds result from the formation of chemical bonds between two or more different elements.

Chemical bond: attractive force holding two or more atoms together.

Ionic Bonds - electron transfer process. Typically between a metal and a nonmetals Covalent Bonds - electrons shared. Typically involving nonmetals.

Ionic compounds Consist of positive and negative ions. Have ionic bonds between positively and negatively charged ions. Have high melting and boiling points. Are solid at room temperature. Ionic Compounds

Salt is An Ionic Compound Sodium chloride (table salt) is an example of an ionic compound. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

An ionic formula Consists of positively and negatively charged ions. Is neutral. Has charge balance. total positive charge = total negative charge Uses subscripts to indicate the number of ions needed to give charge balance. Ionic Formulas

Ionic Formula of NaCl In an ionic formula The symbol of the metal is written first followed by the symbol of the nonmetal. The charges of the ions in the compound are not shown. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

The formulas of ionic compounds are determined from the charges on the ions. atoms ions     – Na  +  F :  Na + : F :  NaF     sodium fluorine sodium fluoride The overall charge of NaF is zero (0). Na + F - = NaF (1+ ) + (1-) = 0 Charge Balance in NaF

Charge Balance In MgCl 2 In forming MgCl 2 A Mg atom loses two valence electrons. Two Cl atoms each gain one electron. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Using Lewis Electron Dot Symbols Br Mg + → Br

Using Lewis Electron Dot Symbols Al + N →

Writing Ionic Formulas from Charges Charge balance is used to write the formula for sodium nitride, a compound containing Na + and N 3−. Na + 3Na + +N 3− = Na 3 N Na + 3(+1) + 1(3-) = 0 Note: the subscript 3 for three sodium ions.

Write the ionic formula of the compound with Ba 2+ and Cl . Write the symbols of the ions. Ba 2+ Cl  Balance the charges. Ba 2+ Cl  two Cl - needed Cl  Write the ionic formula using a subscript 2 for two chloride ions. BaCl 2 Formula from Ionic Charges

Write the correct formula for the ionic compounds formed by the following ions: Learning Check

Naming and Writing Ionic Formulas Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming of Ionic Compounds In the name of an ionic compound The positive ion (first ion) is named as the element. The negative ion (second ion) is named by changing the end of the element name to –ide.

Names of Some Common Ions 3A (13) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Complete the names of the following ions: Ba 2+ Al 3+ K + _________ __________ _________ N 3  O 2  F  _________ ___________________ P 3  S 2  Cl  _________ __________ _________ Learning Check

To name a compound that contains two elements Identify the cation and anion. Name the positive metal ion (cation) as the element. Name the anion by changing the ending to ide. Name the cation first followed by the name of the anion. Naming Ionic Compounds with Two Elements

Charges of Representative Elements Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Formula IonsName NaClNa + Cl - sodium chloride K 2 SK + S 2- potassium sulfide MgOMg 2+ O 2- magnesium oxide CaI 2 Ca 2+ I - calcium iodide Al 2 O 3 Al 3+ O 2- aluminum oxide Some Ionic Compounds with Two Elements

More Ionic Compounds Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Write the formulas and names for compounds of the following ions: N 3− Br − S 2− Na + Al 3+

Write the names of the following compounds: 1) CaO___________ 2) KBr___________ 3) Al 2 O 3 ___________ 4) MgCl 2 ___________

Most Transition Metals form Two or More Positive Ions Most of the transition metals Form 2 or more positive ions. For example, Copper forms Cu + and Cu 2+ Iron forms Fe 2+ and Fe 3+ Gold form Au + and Au 3+

Metals that form more than One Cation Some Metals That Form More Than One Positive Ion Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings Lead Pb 2+ lead(II) Pb 4+ lead(IV)

Periodic Table and Some Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming Variable Charge Metals Transition metals With two different ions use a Roman numeral after the name of the metal to indicate ionic charge. Only zinc, silver, and cadmium form one ion (Zn 2+, Ag +, and Cd 2+ ) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming FeCl 2 To name FeCl 2 [ 1 Iron ion + 2 chloride ions ] 1. Determine the charge of the cation using the charge of the anion (Cl - ). Fe ion + 2 Cl - = 1(?) + 2(1-) = 0 Fe ion = 2+ Fe Name the cation by the element name and a Roman numeral in parenthesis to show charge. Fe 2+ = iron(II) 3. Write the name of the anion with an ide ending. iron(II) chloride = FeCl 2

Naming Cr 2 O 3 To name Cr 2 O 3 1. Determine the charge of cation from the anion (O 2- ). 2Cr ions + 3 O 2- = ? + 3(2-) = ? - 6 = 0 ? = +6 +6/ 2Cr ions = +3 Cr ion = 3+ Cr Name the cation by the element name and use a Roman numeral in parenthesis to show its charge. Cr 3+ = chromium(III) 3. Write the name of the anion with -ide ending. chromium(III) oxide = Cr 2 O 3

Learning Check Select the correct name for each

Writing Formulas Write the formula of potassium sulfide. STEP 1Identify the cation and anion. potassium = K + sulfide = S 2− STEP 2. Balance the charges. K + S 2− K + 2(1+) + 2(1-) = 0 STEP 3. 2 K + and 1 S 2− = K 2 S

Writing Formulas Write the formula of cobalt(III) chloride. STEP1. Identify the cation and anion. cobalt(III) = Co 3+ (III = charge of 3+) chloride = Cl − STEP 2. Balance the charges. Co 3+ Cl − Cl − = (3+) + 3(1-) = 0 Cl − STEP 3. 1 Co 3+ and 3 Cl − = CoCl 3

Learning Check The correct formula for each of the following is: 1. 2.

Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

A polyatomic ion Is a group of atoms. Has an overall ionic charge. Some examples of polyatomic ions are NH 4 + ammoniumOH − hydroxide NO 3 − nitrateNO 2 − nitrite CO 3 2− carbonatePO 4 3− phosphate HCO 3 − hydrogen carbonate (bicarbonate) Polyatomic Ions

Some Compounds with Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

The names of common polyatomic anions End in ate. NO 3 − nitratePO 4 3− phosphate With one oxygen less end in ite. NO 2 − nitritePO 3 3− phosphite With hydrogen attached use prefix hydrogen (or bi). HCO 3 − hydrogen carbonate (bicarbonate) HSO 3 − hydrogen sulfite (bisulfite) More Names of Polyatomic Ions

Names and Formulas of Common Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Names and Formulas of Common Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Polyatomic ions of the halogens require prefixes. ClO 4 − perchlorateone oxygen more ClO 3 − chlorate most common form ClO 2 − chloriteone oxygen less ClO − hypochlorite two oxygens less Prefixes for Names of Polyatomic Ions of Halogens

The positive ion is named first followed by the name of the polyatomic ion. NaNO 3 sodium nitrate K 2 SO 4 potassium sulfate Fe(HCO 3 ) 3 iron(III) bicarbonate or iron(III) hydrogen carbonate (NH 4 ) 3 PO 3 ammonium phosphite Naming Compounds with Polyatomic Ions

Some Compounds with Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Naming Polyatomic Ions Nick the Camel Craved and ate a Clam Supper in Phoenix.

Select the correct formula for each: Learning Check

Match each formula with the correct name: A) magnesium sulfite B) magnesium sulfate C) magnesium sulfide Learning Check

A) calcium chlorate B) calcium chlorite C) calcium hypochlorite

Learning Check Name each of the following compounds: 1. Mg(NO 3 ) 2 2.Cu(ClO 3 ) 2 3.PbO 2 4.Fe 2 (SO 4 ) 3 5.Ba 3 (PO 3 ) 2

Writing Formulas with Polyatomic Ions The formula of an ionic compound Containing a polyatomic ion must have a charge balance that equals zero(0). Na + and NO 3 − →NaNO 3 With two or more polyatomic ions encloses the polyatomic ions in parentheses. Mg 2+ and 2NO 3 − → Mg(NO 3 ) 2 subscript 2 for charge balance

Learning Check Write the correct formula for each: 1.potassium bromate 2.calcium carbonate 3.sodium phosphate 4.iron(III) oxide 5.iron(II) nitrite

Naming Ionic Compounds Review: Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Flowchart for Naming Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Name the following compounds: A. Ca 3 (PO 4 ) 2 B. FeBr 3 C. Al 2 S 3 D. Mn(NO 2 ) 2 E. NaHCO 3

Learning Check Write the formulas for the following: A. calcium nitrate B. iron(II) hydroxide C. aluminum carbonate D. copper(II) hypobromite E. lithium phosphate

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

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

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

Diatomic Elements These elements share electrons to form diatomic covalent molecules or molecular elements Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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 if they exist. A central atom with an octet. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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

Names of Covalent Compounds Prefixes are used In the names of covalent compounds. Because typically 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

Naming Covalent Compounds STEP 1 Name the first nonmetal as the element. STEP 2 End the name of the second nonmetal with -ide STEP 3 Use prefixes to show the number of atoms (subscripts). Mono is usually omitted. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

What is the name of SO 3 ? STEP 1 The first nonmetal is S sulfur. STEP 2 The second nonmetal is O named oxide. STEP 3 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

Name P 4 S 3 STEP 1 The first nonmetal P is phosphorus. STEP 2 The second nonmetal S is sulfide. STEP 3 The subscript 4 of P is shown as tetra. The subscript 3 of S is shown as tri. P 4 S 3 → tetraphosphorus trisulfide Naming Covalent Compounds

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

Select the correct name for each compound. A.SiCl 4 1) 2) 3) B. P 2 O 5 1) 2) 3) C.Cl 2 O 7 1) 2) 3) Learning Check

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

STEP 1 Write the symbols in the order of the elements in the name. STEP 2 Write any prefixes as subscripts. Example: Write the formula for carbon disulfide. STEP 1 Elements are C and S STEP 2 No prefix for carbon means 1 C Prefix di = 2 Formula: CS 2 Guide to Writing Formulas

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

Identify each compound as ionic or covalent and give its correct name. 1. SO 3 2. MnCl 2 3. (NH 4 ) 3 PO 3 4. Cu 2 CO 3 5. N 2 O 4

Learning Check Identify each compound as ionic or covalent and give its correct name. 1.Ca 3 (PO 4 ) 2 2.FeBr 3 3.SCl 2 4.Cl 2 O