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Bellwork: Monday 4/9/2012 Naming Covalent Compounds

Bellwork: Monday 4/9/2012 Naming Covalent Compounds. F 2 Fluorine gas Cl 2 Chlorine gas HF Hydrogen fluoride HCl Hydrogen chloride H 2 S Dihydrogen sulfide. NO Nitrogen monoxide NO 2 Nitrogen dioxide NO 3 Nitrogen trioxide N 2 O Dinitrogen monoxide.

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Bellwork: Monday 4/9/2012 Naming Covalent Compounds

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  1. Bellwork: Monday 4/9/2012Naming Covalent Compounds • F2 • Fluorine gas • Cl2 • Chlorine gas • HF • Hydrogen fluoride • HCl • Hydrogen chloride • H2S • Dihydrogen sulfide • NO • Nitrogen monoxide • NO2 • Nitrogen dioxide • NO3 • Nitrogen trioxide • N2O • Dinitrogen monoxide

  2. Naming Covalent Compounds- pg 5 Formulas to Names Names to Formulas • Silicon tetrachloride • Carbon disulfide • Tetraphosphoruspentasulfide • Phosphorus trihydride • Antimony tribromide • Disiliconhexabromide • Carbon tetrafluoride • Dinitrogen trioxide • Sulfur hexachloride • Sulfur trioxide • B2H6 • ClO2 • NBr3 • SeF6 • XeF6 • B6Si • BF3 • NF3 • P2O5 • SiF4

  3. Review: Classifying Chemical Bonds • Covalent bondsare those between non-metals and non-metalsEx: C (non-metal) and H (non-metal)  CH4 • Ionic bondsare those between metals and non-metalsEx: K (metal) and O (non-metal)  K2O • Metallic bondsare those between metals and metals

  4. METALSvsNON-METALS H H Metalloids (dual properties) B "GENEROUS" Al Si with their electrons As Ge Sb Te Po At "GREEDY" with their electrons

  5. Opposite charges attract! Same charges repel! Understanding how ions react to other elements will help in naming compounds or coming up with formulas for the compounds.

  6. To become happy… Get more? OR Get rid of ‘em? Li Be B C • What is the charge? 2e- 6p+ 3p+ 4p+ 5p+ +1 +4 I VII VIII +2 +3 -4 II III IV V VI

  7. To become happy… Get more? OR Get rid of ‘em? N O F Ne Na • What is the charge? 8e- 2e- 8p+ 10p+ 11p+ 9p+ 7p+ +1 -1 0 +4 I VII VIII +2 +3 -4 -3 -2 II III IV V VI

  8. -1 +2 F Be 2e- 2e- 4p+ 9p+ +1 -1 0 +4 I VII VIII +2 +3 -4 -3 -2 II III IV V VI

  9. F-1 Be+2 F-1 2e- 2e- 2e- 4p+ 9p+ 9p+ +1 -1 0 +4 I VII VIII +2 +3 -4 -3 -2 Beryllium fluoride II III IV V VI BeF2

  10. -1 -1 -1 +3 Cl Cl Al Cl -1 +3 Cl Al +1 +4 -1 0 +3 -4 -3 -2 I VII VIII +2 Aluminum chloride II III IV V VI AlCl3

  11. 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) • 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. • Anion- When an atom gains an e- it gains a negative charge & becomes a negative ion.

  12. Lithium • Calcium • Chlorine • Selenium • Arsenic • Li+1 • Ca+2 • Cl-1 • Se-2 • As-3 • 1 • 2 • 7 • 6 • 5 • Lose 1 e’ • Lose 2 e’ • Gain 1 e’ • Gain 2 e’ • Gain 3 e’ I VII VIII II III IV V VI

  13. Ionic compounds are electrically neutral • Goal: Balance out the charges • Sum of all oxidation numbers in compound = ZERO • Ex: Magnesium and Chlorine = Magnesium chloride • What is the charge of Chlorine?Magnesium? • How many chlorineions are needed to balance the magnesiumions? 2 Cl-1 ions balance 1 Mg+2 ion Mg+2Cl-12

  14. Drawing Ionic Compounds -2 +2 Mg O Mg+2O-2 Magnesium oxide • 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

  15. Drawing Ionic Compounds Occasionally, you may need more than just one atom to fulfill each atom’s Octet rule… “-1” tells that each Bromine atom has gained 1 e- to become (-) “+3” tells that Nickel has lost 3 e-s to become (+) Br Br -1 +3 Ni Br 3 Ni Br “3” tells that 3 Bromine atoms are needed to stabilize 1 atom of Nickel Ex: Ni + Br = Nickel (III) bromide

  16. Ionic bonding: Al + Cl Al Cl Cl Cl Al+3 Cl3–1 Aluminum chloride NOW: Try it yourself on pages 7 & 8!

  17. Bellwork: Tuesday 4/10/2012 Mg & ClAl & Cl • Draw a diagram to show how they ionically bond to form neutral compounds. • What is the formula? What is the name? Magnesium chloride Cl2-1  Mg+2 Aluminum chloride  Cl3-1 Al+3

  18. K+1 F-1 O-2 Na2+1 

  19. I2-1 Mg+2   S-2 Be+2

  20. Al+3 Br3-1  F3-1 B+3

  21. Ca2+2 Si-4 1  S-2 K2+1

  22. Mg3+2 N2-3  Al2+3 O3-2

  23. Naming Simple Ionic Compounds- Pg 8 • When writing the name of ionic compounds: • The first atom listed… • Is the cation (+) • Is capitalized • Is written as the name of that element • The second atom listed… • Is the anion (-) • Is written in lowercase • Is shortened • Ends in the suffix “-ide” Ex: Fe2O3 +3 -2 …is Iron oxide

  24. Try to Name These Compounds! Sodium bromide • NaBr • CaO • Li2S • MgBr2 • Be(OH)2 Calcium oxide Lithium sulfide Magnesium bromide Beryllium hydroxide

  25. Writing Ionic Names to Formulas • When writing an ionic compound’s formula, you need to find the following: • The atomic symbols for each element • 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!  • ADD this example at the bottom of the “Names to Formulas” Table! +2 -2 Ca O CaO Calcium oxide

  26. Now let’s try to write the chemical symbols for each compound KI I-1 K+1 • Potassium iodide • Magnesium oxide • Aluminum chloride • Magnesium hydroxide • Calcium Oxide Mg+2 O-2 MgO Al+3 Cl-1 AlCl3 Mg(OH)2 OH-1 Mg+2 O-2 Ca+2 CaO

  27. 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 • Fe+2 = Iron (II) • Fe+3 = Iron (III) • Assume you need a roman numeral for all metals, except: • Metals in group I and II • Aluminum (Al), Cadmium (Cd), Silver (Ag), and Zinc (Zn)

  28. 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 • 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

  29. Naming Ionic Compounds • 1st Word: Name the cation (positive ion) • Usually the full name of the metal • 2nd Word: Name the anion (negative ion) • Element: • 1st syllable; ends in “-ide” • Polyatomic Ion: • Unchanged name of polyatomic ion • Does the metal have a Fixed Oxidation Number? • 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 • Charge expressed as roman numeral, in parenthesis, after the name of the metal CaSO4 Ca?SO4-2 Ca+2 Fixed oxidation number Calcium sulfate

  30. Naming Ionic Compounds • 1st Word: Name the cation (positive ion) • Usually the full name of the metal • 2nd Word: Name the anion (negative ion) • Element: • 1st syllable; ends in “-ide” • Polyatomic Ion: • Unchanged name of the polyatomic ion • Does the metal have a Fixed Oxidation Number? • 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 • 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 • Total oxidation state must be zero • Positive charge must equal the total negative charge • A simple algebraic equation can be used to determine CuSO4 Cu?SO4-2 x + (-2) = 0 x = 2 Copper (II) sulfate

  31. Examples #1- Formulas to Names CuSO3 1. Write the names of the ions = 0 2. Determine the charge of the positive ion Cu +2 SO3 x -2 X + (- 2) = 0 You must know the charge on the sulfite ion is -2 I’m a polyatomic ion +2 +2 The sum of the positive and negative charges must equal zero X = +2 (II) Copper sulfite Final Name

  32. Examples #2- Formulas to Names KMnO4 1. Write the names of the ions I’m a polyatomic ion Potassium permanganate Final Name If the positive ion has a fixed charge, you are finished.

  33. Examples #3- Formulas to Names NH4NO3 1. Write the names of the ions 2. Determine the charge of the positive ion I’m a polyatomic ion I’m a polyatomic ion Ammonium nitrate Final Name If the positive ion has a fixed charge, you are finished.

  34. Examples #4- Formulas to Names SnF2 1. Write the names of the ions X = +2 2. Determine the charge of the positive ion X + 2(-1) = 0 Snx (F-1)2= 0 (II) fluoride Tin Final Name

  35. Examples #5- Formulas to Names Ba(ClO4)2 1. Write the names of the ions 2. Determine the charge of the positive ion I’m a polyatomic ion Barium perchlorate Final Name If the positive ion has a fixed charge, you are finished.

  36. Examples #6- Formulas to Names Cu2S 1. Write the names of the ions X = +1 2. Determine the charge of the positive ion 2X + (-2) = 0 2CuxS-2= 0 I’m NOT a polyatomic ion (I) Copper sulfide Final Name

  37. Examples #7- Formulas to Names Na2Cr2O7 1. Write the names of the ions 2. Determine the charge of the positive ion I’m a polyatomic ion Sodium dichromate Final Name If the positive ion has a fixed charge, it is not shown

  38. Examples #8- Formulas to Names LiCN 1. Write the names of the ions 2. Determine the charge of the positive ion I’m a polyatomic ion Lithium cyanide Final Name If the positive ion has a fixed charge, you are finished.

  39. 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

  40. Example #1-Names to Formulas Aluminumchloride 1. Write symbols of elements (Al )x(Cl-1)y +3 2. Determine number of ions This formula says that the +3 charge of one Al atom will cancel the-3 charge from 3 Cl atoms x(+3) +y(-1) = 0 1(+3) +3(-1) = 0 Cl Al 3 1 Final Formula If there is only one atom the “1” is not shown

  41. Example #2-Names to Formulas X1 = Y2 Cobalt (II) bromate 2X = 1y 1. Write symbols of elements X(+2) +y(-1) = 0 2. Determine number of ions (Co+2)x(BrO3-1)y= 0 Choose the lowest set of integers thatsatisfies the equation ( )2 BrO3 Co 1 Final Formula If there is only one atom the “1” is not shown

  42. Example #3-Names to Formulas X1 = Y 3 Nickel (III) acetate 1. Write symbols of elements 3X = 1y X(+3) + y(-1) = 0 2. Determine number of ions (Ni+3)x(C2H3O2-1)y= 0 Choose the lowest set of integers thatsatisfies the equation ( )3 C2H3O2 Ni 1 Final Formula If there is only one atom the “1” is not shown

  43. Example #4-Names to Formulas X3 = Y1 Lithium phosphate 1X = 3y 1. Write symbols of elements X(+1) + y(-3) = 0 2. Determine number of ions (Li )x(PO4-3)y= 0 +1 PO4 Li ( )1 3 Final Formula If there is only one atom the “1” is not shown

  44. What do you notice about the numbers in the formula for NiBr3? +3 -1 Ni Br • 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 sum of the product of the “oxidation numbers” and the product of the “# of atoms” in the compound must equal zero (1) 3 (3 × -1) + (1 × 3) = 0

  45. The "Criss-Cross Method" • 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 • Oxygen has an oxidation number of -2 • When you cross them… • …you find the formula for Aluminum Oxide is Al2O3 +3 -2 Al O Al O + 2 3 2 3

  46. How does it Work? +3 -2 • The criss-cross method tells how many of each atom are needed to satisfy each atom’s valence shells • Ex: Aluminum + Oxygen Al O + 3 2 Still more electrons? We must need another Oxygen! Hmm… We still have more electrons…we must need another Oxygen! FINALLY!!! We’re done.  Al O Oops! Now “O” has extras…Need another “Al”! 2 3

  47. Your turn! • 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 + Si-4 Ca4Si2 Na+1+ Br-1 NaBr B+3+ BF3 F-1 S-2 K2S K+1+

  48. Names to Formulas: Criss-Cross Method Bariumnitrate 1. Write the formulas for the cation and anion, including CHARGES! ( ) Ba2+ NO3- 2 2. Check to see if charges are balanced. Now balanced. Not 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. = Ba(NO3)2

  49. Names to Formulas: Criss-Cross Method Iron (III) chloride 1. Write the formulas for the cation and anion, including CHARGES! Fe3+ Cl- 3 2. Check to see if charges are balanced. Now balanced. Not 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. = FeCl3

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