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Bellwork: Monday 4/9/2012 Naming Covalent Compounds 1. 1. F 2 Fluorine gas 2. 2. Cl 2 Chlorine gas 3. 3. HF Hydrogen fluoride 4. 4. HCl Hydrogen chloride 5. 5. H 2 S Dihydrogen sulfide 6. 6. NO Nitrogen monoxide 7. 7. NO 2 Nitrogen dioxide 8. 8. NO 3 Nitrogen trioxide 9. 9. N 2 O Dinitrogen monoxide
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Naming Covalent Compounds- pg 5 Formulas to NamesNames to Formulas 1. Silicon tetrachloride 2. Carbon disulfide 3. Tetraphosphorus pentasulfide 4. Phosphorus trihydride 5. Antimony tribromide 6. Disilicon hexabromide 7. Carbon tetrafluoride 8. Dinitrogen trioxide 9. Sulfur hexachloride 10. Sulfur trioxide 1. B 2 H 6 2. ClO 2 3. NBr 3 4. SeF 6 5. XeF 6 6. B 6 Si 7. BF 3 8. NF 3 9. P 2 O 5 10. SiF 4
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Review: Classifying Chemical Bonds Covalent bonds are those between non-metals and non-metals Ex: C (non-metal) and H (non-metal) CH 4 Ionic bonds are those between metals and non-metals Ex: K (metal) and O (non-metal) K 2 O Metallic bonds are those between metals and metals
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Si As Al Ge Sb Po B Te At H H Metalloids (dual properties) METALS vs NON-METALS
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Understanding how ions react to other elements will help in naming compounds or coming up with formulas for the compounds. Opposite charges attract! Same charges repel!
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2e - 3p + 4p + LiBe B 5p + 6p + C To become happy… Get more? OR Get rid of ‘em? I II IIIVIVIV +1 +2 +3-4 VIIVIII What is the charge? +4
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2e - NOF 7p + 8p + 9p + 10p + Ne 8e - Na 11p + I II IIIVIVIV +4 +1 +2 +3-4-2 -3 0 VIIVIII To become happy… Get more? OR Get rid of ‘em? What is the charge?
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2e - 4p + Be 2e - F 9p + I II IIIVIVIV +4 +1 +2 +3-4-2 -3 0 VIIVIII +2
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2e - 4p + Be +2 2e - F -1 9p + 2e - F -1 9p + I II IIIVIVIV +4 +1 +2 +3-4-2 -3 0 VIIVIII Beryllium fluoride BeF 2
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Al +3 Cl Cl Cl Al +3 Cl I II IIIVIVIV +4+1 +2 +3-4-2 -3 0 VIIVIII AlCl 3 Aluminum chloride
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Ionic Bonding- Page 7 Ionic Bonding- Bond between metal and non-metal Transfer of electrons, which results in positive or negative charged ions that attract to each other (opposites attract) Transfer of electrons, which results in positive or negative charged ions that attract to each other (opposites attract) The greater the charge, the greater the attraction The greater the charge, the greater the attraction Oxidation number - how many electrons an atom has gained, lost, or shared to become stable; the charge (+ or -) Cation- When an atom loses an e-, it loses a negative charge & becomes a positive ion. Cation- When an atom loses an e-, it loses a negative charge & becomes a positive ion. Anion- When an atom gains an e- it gains a negative charge & becomes a negative ion. Anion- When an atom gains an e- it gains a negative charge & becomes a negative ion.
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Lithium Lithium Calcium Calcium Chlorine Chlorine Selenium Selenium Arsenic Arsenic Li +1 Li +1 Ca +2 Ca +2 Cl -1 Cl -1 Se -2 Se -2 As -3 As -3 I II IIIVIVIV VIIVIII 1 2 7 6 5 Lose 1 e’ Lose 1 e’ Lose 2 e’ Lose 2 e’ Gain 1 e’ Gain 1 e’ Gain 2 e’ Gain 2 e’ Gain 3 e’ Gain 3 e’ Element Name # of Valence e’ How it’s going to get happy How it’s going to get happy Ion it would form
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Ionic compounds are electrically neutral Goal: Balance out the charges Goal: Balance out the charges Sum of all oxidation numbers in compound = ZERO Sum of all oxidation numbers in compound = ZERO Ex: Magnesium and Chlorine = Magnesium chloride What is the charge of Chlorine? Magnesium? What is the charge of Chlorine? Magnesium? How many chlorine ions are needed to balance the magnesium ions? How many chlorine ions are needed to balance the magnesium ions? 2 Cl -1 ions balance 1 Mg +2 ion Mg +2 Cl -1 2
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Mg loses 2 electrons to become stable, becoming positively charged Mg +2 O gains the 2 electrons to become stable, so O becomes negatively charged O -2 MgO Mg +2 O -2 +2 -2 Magnesium oxide
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Br Ni Occasionally, you may need more than just one atom to fulfill each atom’s Octet rule… Br Ex: Ni + Br = Nickel (III) bromide Ni Br +3 3 “+3” tells that Nickel has lost 3 e - s to become (+) “-1” tells that each Bromine atom has gained 1 e - to become (-) “3” tells that 3 Bromine atoms are needed to stabilize 1 atom of Nickel
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Ionic bonding: Al + Cl Al +3 Cl 3 –1 ClAlCl Aluminum chloride NOW: Try it yourself on pages 7 & 8!
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Bellwork: Tuesday 4/10/2012 Mg & Cl Al & Cl 1. Draw a diagram to show how they ionically bond to form neutral compounds. 2. What is the formula ? What is the name ? Magnesium chloride Mg +2 Cl 2 -1 Al +3 Cl 3 -1 Aluminum chloride
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K +1 F -1 Na 2 +1 O -2
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Be +2 S -2 Mg +2 I 2 -1
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B +3 F 3 -1 Al +3 Br 3 -1
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K 2 +1 1 S -2 Ca 2 +2 Si -4
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Al 2 +3 O 3 -2 Mg 3 +2 N 2 -3
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Naming Simple Ionic Compounds- Pg 8 When writing the name of ionic compounds: The first atom listed… Is the cation (+) Is the cation (+) Is capitalized Is capitalized Is written as the name of that element Is written as the name of that element The second atom listed… Is the anion (-) Is the anion (-) Is written in lowercase Is written in lowercase Is shortened Is shortened Ends in the suffix “-ide” Ends in the suffix “-ide” Ex: Fe 2 O 3 …is Iron oxide +3-2
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1) NaBr 2) CaO 3) Li 2 S 4) MgBr 2 5) Be(OH) 2 Sodium bromide Calcium oxide Lithium sulfide Magnesium bromide Beryllium hydroxide
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Writing Ionic Names to Formulas When writing an ionic compound’s formula, you need to find the following: The atomic symbols for each element The atomic symbols for each element Oxidation Numbers - *Remember: these tell you how many of each atom you need! Oxidation Numbers - *Remember: these tell you how many of each atom you need! ○ *NOTE: If the Oxidation Numbers are the same, you DO NOT need to write them anywhere in the formula! ○ *NOTE: If the Oxidation Numbers are the same, you DO NOT need to write them anywhere in the formula! ADD this example at the bottom of the “Names to Formulas” Table! Calcium oxide Ca +2 CaOO -2
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Now let’s try to write the chemical symbols for each compound 1) Potassium iodide 2) Magnesium oxide 3) Aluminum chloride 4) Magnesium hydroxide 5) Calcium Oxide KIKIKIKI MgO AlCl 3 Mg(OH) 2 K +1 O -2 Mg +2 Cl -1 Al +3 OH -1 Mg +2 I -1 Ca +2 O -2CaO
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Naming Complicated Ionic Compounds: Metals that form MORE THAN ONE ION Periodic Chart of Ions- Page 11 What ions does Iron (Fe) form? Ions: Fe +2 or Fe +3 Use roman numerals for charge Use roman numerals for charge ○ Fe +2 = Iron (II) ○ Fe +3 = Iron (III) Roman numeral Charge I+1 II+2 III+3 IV+4 V+5 VI+6 Assume you need a roman numeral for all metals, except: Metals in group I and II Metals in group I and II Aluminum (Al), Cadmium (Cd), Silver (Ag), and Zinc (Zn) Aluminum (Al), Cadmium (Cd), Silver (Ag), and Zinc (Zn)
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Naming Complicated Ionic Compounds: POLYATOMIC IONS “more than one atom” ions Common Polyatomic Ions- Page 9 Ions made up of two or more atoms Made of two non-metals Covalently bonded together Covalently bonded together When they bond with another ion, an ionic bond forms Think of them as a group of atoms that react as ONE! Remember: CO and Co are different! The second letter of an atomic symbol is always lowercase Remember: CO and Co are different! The second letter of an atomic symbol is always lowercase
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Naming Ionic Compounds 1 st Word: Name the cation (positive ion) Usually the full name of the metal Usually the full name of the metal 2 nd Word: Name the anion (negative ion) Element: Element: ○ 1 st syllable; ends in “-ide” Polyatomic Ion: Polyatomic Ion: ○ Unchanged name of polyatomic ion Does the metal have a Fixed Oxidation Number ? FIXED- NO roman numeral is used FIXED- NO roman numeral is used ○ You know the charge of the fixed ions!! (Group 1, 2, 13, etc.) FORMS MORE THAN ONE ION- YES use roman numeral FORMS MORE THAN ONE ION- YES use roman numeral ○ Charge expressed as roman numeral, in parenthesis, after the name of the metal CaSO 4 Ca ? SO 4 -2 Ca +2 sulfate Calcium Fixed oxidation number
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Naming Ionic Compounds 1 st Word: Name the cation (positive ion) Usually the full name of the metal Usually the full name of the metal 2 nd Word: Name the anion (negative ion) Element: Element: ○ 1 st syllable; ends in “-ide” Polyatomic Ion: Polyatomic Ion: ○ Unchanged name of the polyatomic ion Does the metal have a Fixed Oxidation Number ? FIXED- NO roman numeral is used FIXED- NO roman numeral is used ○ You know the charge of the fixed ions!! (Group 1, 2, 13, etc.) FORMS MORE THAN ONE ION- YES use roman numeral FORMS MORE THAN ONE ION- YES use roman numeral ○ Charge expressed as roman numeral, in parenthesis, after the name of the metal The oxidation number on the negative ion determines the charge on the positive ion The oxidation number on the negative ion determines the charge on the positive ion Total oxidation state must be zero Total oxidation state must be zero ○ Positive charge must equal the total negative charge ○ A simple algebraic equation can be used to determine CuSO 4 Cu ? SO 4 -2 x + (-2) = 0 sulfate Copper x = 2 (II)
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Examples #1- Formulas to Names CuSO 3 Copper I’m a polyatomic ion 1.Write the names of the ions Final Name sulfite (II) x X + (- 2) = 0 X = +2 Cu SO 3 = 0 You must know the charge on the sulfite ion is -2 The sum of the positive and negative charges must equal zero 2. Determine the charge of the positive ion -2 +2
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Examples #2- Formulas to Names KMnO 4 Potassium I’m a polyatomic ion 1.Write the names of the ions Final Name permanganate If the positive ion has a fixed charge, you are finished.
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Examples #3- Formulas to Names NH 4 NO 3 Ammonium I’m a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name nitrate If the positive ion has a fixed charge, you are finished. I’m a polyatomic ion
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Examples #4- Formulas to Names SnF 2 Tin 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name fluoride (II) Sn x (F -1 ) 2 = 0 X + 2(-1) = 0 X = +2
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Examples #5- Formulas to Names Ba(ClO 4 ) 2 Barium I’m a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name perchlorate If the positive ion has a fixed charge, you are finished.
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Examples #6- Formulas to Names Cu 2 S Copper I’m NOT a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name sulfide (I) 2Cu x S -2 = 0 2X + (-2) = 0 X = +1
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Examples #7- Formulas to Names Na 2 Cr 2 O 7 Sodium I’m a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name dichromate If the positive ion has a fixed charge, it is not shown
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Examples #8- Formulas to Names LiCN Lithium I’m a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name cyanide If the positive ion has a fixed charge, you are finished.
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Writing Names to Formulas It is easier to write the formula of an ionic compound from its name than the reverse. But, you must know the oxidation number of the ions! Refer to the table of common polyatomic ions Refer to the table of common polyatomic ions
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Example #1-Names to Formulas Aluminum chloride Aluminum chloride Al Cl 3 2. Determine number of ions 1. Write symbols of elements Final Formula x(+3) + y(-1) = 0 1 If there is only one atom the “1” is not shown +3 (Al ) x (Cl -1 ) y 1(+3) + 3(-1) = 0 This formula says that the +3 charge of one Al atom will cancel the-3 charge from 3 Cl atoms
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Example #2-Names to Formulas Cobalt (II) bromate Cobalt (II) bromate Co BrO 3 2. Determine number of ions 1. Write symbols of elements Final Formula (Co +2 ) x (BrO 3 -1 ) y = 0 2X = 1y X(+2) + y(-1) = 0 X 1 Y 2 = 1 Choose the lowest set of integers that satisfies the equation If there is only one atom the “1” is not shown ( ) 2
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Example #3-Names to Formulas Nickel (III) acetate Nickel (III) acetate Ni C2H3O2C2H3O2 2. Determine number of ions 1. Write symbols of elements Final Formula (Ni +3 ) x (C 2 H 3 O 2 -1 ) y = 0 3X = 1y X(+3) + y(-1) = 0 X 1 Y 3 = 1 Choose the lowest set of integers that satisfies the equation ( ) 3 If there is only one atom the “1” is not shown
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Example #4-Names to Formulas Lithium phosphate Li PO 4 2. Determine number of ions 1. Write symbols of elements Final Formula (Li ) x (PO 4 -3 ) y = 0 1X = 3y X(+1) + y(-3) = 0 X 3 Y 1 = 3 +1 ( ) 1 If there is only one atom the “1” is not shown
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What do you notice about the numbers in the formula for NiBr 3 ? When criss-crossed, they are equal! The top numbers for each atom are called its Oxidation Number The oxidation number tells you how many electrons an atom has gained, lost, or shared to become stable The oxidation number tells you how many electrons an atom has gained, lost, or shared to become stableoxidation numberelectronsoxidation numberelectrons The sum of the product of the “oxidation numbers” and the product of the “# of atoms” in the compound must equal zero Ni Br +3 3(1) (3 × -1) + (1 × 3) = 0
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The oxidation numbers may be may be criss- crossed to create subscripts in the formula, and used to help write the chemical formulas This is called the “Criss-Cross Method” For example: when creating “Aluminum oxide” Aluminum has an oxidation number of +3 Aluminum has an oxidation number of +3 Oxygen has an oxidation number of -2 Oxygen has an oxidation number of -2 When you cross them… When you cross them… …you find the formula for Aluminum Oxide is Al 2 O 3 …you find the formula for Aluminum Oxide is Al 2 O 3 AlO Al O +3-2 + 23 23
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The criss-cross method tells how many of each atom are needed to satisfy each atom’s valence shells Ex: Aluminum + Oxygen Al O 23 Oops! Now “O” has extras…Need another “Al”! Hmm… We still have more electrons… we must need another Oxygen! Still more electrons? We must need another Oxygen! FINALLY!!! We’re done. AlO +3-2 + 23
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Try to use the Criss-Cross Method to find the formulas for the following situations: Calcium + Silicon Sodium + Bromine Boron + Fluorine Potassium + Sulfur Ca +2 + Na +1 + B +3 + K +1 + Si -4 Ca 4 Si 2 NaBr Br -1 F -1 BF 3 S -2 K2SK2SK2SK2S
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Names to Formulas: Criss-Cross Method Barium Barium nitrate 1. Write the formulas for the cation and anion, including CHARGES! Ba 2+ NO 3 - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts. Not balanced! ( ) 2 Now balanced. = Ba(NO 3 ) 2
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Iron (III) Iron (III) chloride Fe 3+ Cl - Not balanced! 3 Now balanced. = FeCl 3 Names to Formulas: Criss-Cross Method 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts.
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Ammonium Ammonium sulfate NH 4 + SO 4 2- Not balanced! ( ) 2 Now balanced. = (NH 4 ) 2 SO 4 Names to Formulas: Criss-Cross Method 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts.
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Aluminum Aluminum sulfide Al 3+ S 2- Not balanced! 23 Now balanced. = Al 2 S 3 Names to Formulas: Criss-Cross Method 1. Write the formulas for the cation and anion, including CHARGES! 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts.
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