1. Chemical Nomenclature

2. Octet Rule n Atoms tend to achieve electron configuration of Noble Gases n Octet = Eight n Noble Gases have eight electrons in their highest energy level n General Equation for Noble Gases is S 2 P 6

3. n Atoms of Metallic Elements tend to lose valence electron/s, leaving an octet in the next lowest energy level n Atoms of a Non-Metallic Element tend to gain a valence electron/s to achieve an Octet n There are EXCEPTIONS to the Octet Rule

4. © 2009, Prentice-Hall, Inc. Diatomic Molecules These eight elements occur naturally as molecules containing two atoms. Astatine is considered a diatomic

5. Ions n Atoms or groups of atoms with a charge n Cations- positive ions - get by losing electrons(s) n Anions- negative ions - get by gaining electron(s) n Ionic bonding- held together by the opposite charges n Ionic solids are called salts

6. n Even though atoms and cations have the same name, there are many chemical differences between metals and their cations. n Example: n Na Metal; reacts explosively in water n Na Cation; quite unreactive

7. Cations l Positive ions. l Formed by losing electrons. l More protons than electrons. l Metals form cations. K +1 Has lost one electron Ca +2 Has lost two electrons

8. Anion n A negative ion. n Has gained electrons. n Non metals can gain electrons. n Charge is written as a super script on the right. F -1 Has gained one electron O -2 Has gained two electrons

9. Charges on ions n For most of the Group A elements, the Periodic Table can tell what kind of ion they will form from their location. n Elements in the same group have similar properties. n Including the charge when they are ions.

10. n Monatomic Ions- consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons n Groups 1a, 2a, and 3a lose electrons and form cations n Aluminum is the only common group 3a element to lose electrons and form a cation

11. n Non-metals tend to gain electrons and form an anion. n Groups 5a, 6a, and 7a form anions n In group 5a, there are three non-metals which form anions n N 3-, P 3-, & As 3-

12. n Majority of elements in 4a & 0 do not form ions n Group 0 rarely forms compounds n Ordinarily, two non-metals from group 4a, C & Si are found in molecular compounds

13. +1+2-2-3

14. Laws n Conservation of Mass n Law of Definite Proportion- compounds have a constant composition by mass. n They react in specific ratios by mass. n Multiple Proportions- When two elements form more than one compound, the ratios of the masses of the second element that combine with one gram of the first can be reduced to small whole numbers.

15. © 2009, Prentice-Hall, Inc. Law of Constant Composition Joseph Proust (1754–1826) n This is also known as the law of definite proportions. n It states that the elemental composition of a pure substance never varies.

16. © 2009, Prentice-Hall, Inc. Law of Conservation of Mass The total mass of substances present at the end of a chemical process is the same as the mass of substances present before the process took place.

17. Compounds n Follow the Law of Definite Proportion. n Have a constant composition. n Have to add the same number of atoms every time. n Two types.

18. Molecular Compounds Molecular compounds n Made of molecules. n Made by joining nonmetal atoms together into molecules.

19. Ionic Compound Ionic Compounds n Made of cations and anions. n Metals and nonmetals. n The electrons lost by the cation are gained by the anion. n The cation and anions surround each other. n Smallest piece is a FORMULA UNIT.

20. Formula Unit n Formula Unit- lowest whole-number ratio of the ions in the compound n Example n Na + Cl - n Ratio is 1:1 n The formula unit is NaCl

21. Formula Unit n The smallest whole number ratio of atoms in an ionic compound. n Ions surround each other so you can’t say which is hooked to which.

22. Two Types of Compounds Smallest piece Melting Point State Types of elements Formula UnitMolecule Metal and Nonmetal Nonmetals solid liquid or gas High >300ºCLow <300ºC IonicMolecular

23. © 2009, Prentice-Hall, Inc. Types of Formulas n Empirical formulas give the lowest whole- number ratio of atoms of each element in a compound. n Molecular formulas give the exact number of atoms of each element in a compound.

24. Writing Formulas n Two sets of rules, ionic and covalent n To decide which to use, decide what the first word is. n If is a metal or polyatomic use ionic. n If it is a non-metal use covalent

25. © 2009, Prentice-Hall, Inc. Writing Formulas n Because compounds are electrically neutral, one can determine the formula of a compound this way: –The charge on the cation becomes the subscript on the anion. –The charge on the anion becomes the subscript on the cation. –If these subscripts are not in the lowest whole-number ratio, divide them by the greatest common factor.

26. Ionic Formulas n Charges must add up to zero n get charges from table, name of metal ion, or memorized from the list n use parenthesis to indicate multiple polyatomics

27. Ionic Formulas n Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N -3

28. Ionic Formulas n Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N -3 n doesn’t add up to zero Na +1 N -3

29. Ionic Formulas n Sodium nitride n sodium- Na is always +1 n nitride - ide tells you it comes from the table n nitride is N -3 n doesn’t add up to zero n Need 3 Na Na +1 N -3 Na 3 N

30. Writing Formulas n Write the formula for calcium chloride. n Calcium is Ca +2 n Chloride is Cl -1 n Ca +2 Cl -1 would have a +1 charge. n Need another Cl -1 n Ca +2 Cl 2 -1

31. Crisscross n Switch the numerical value of the charges Ba 2+ N 3- 2 3 Ba 3 N2N2 Reduce ratio if possible

32. Polyatomic Ions n Polyatomic Ion- Tightly bound groups of atoms that behave as a unit and carry a charge n Unlike monatomic ions; Sulfate anion is composed of 1 Sulfur atom and 4 oxygen atoms n These five atoms form a Sulfate Anion n It has a –2 charge an is written SO 4 2-

33. n Polyatomic anions either end in ITE or ATE n Out of the two similar polyatomic ions, the polyatomic with less Oxygens ends in ite n Example: n Sulfite and Sulfate n Sulfite; SO 3 2- n Sulfate; SO 4 2-

34. n There are three exceptions to the Polyatomic Rule n 1) Ammonium NH 4 + ---- The only positive polyatomic ion n 2) Cyanide CN - ---- Ends in IDE n 3) Hydroxide OH - --- Ends in IDE

35. Write the formulas for these n Lithium sulfide n tin (II) oxide n tin (IV) oxide n Magnesium fluoride n Copper (II) sulfate n Iron (III) phosphide n gallium nitrate n Iron (III) sulfide

36. Ionic Compounds n Sodium sulfite n calcium iodide n Lead (II) oxide n Lead (IV) oxide n Mercury (I) sulfide n Barium chromate n Aluminum hydrogen sulfate n Cerium (IV) nitrite

37. Write the formulas for these n Ammonium chloride n ammonium sulfide n barium nitrate

38. Naming compounds n Two types n Ionic - metal and non metal or polyatomics n Covalent- we will just learn the rules for 2 non-metals

39. n There are two methods for naming cations with multiple charges n The Stock System and Classical System n The Stock system is the preferred method

40. Stock System n The stock system uses roman numerals in ( ). The ( ) indicate the numerical charge of the cation. Example: Fe 2+ Name: Iron(II) There is no space between the name and the parenthesis Example: Cu 1+ Name: Copper(1)

41. Classical System n The classical system uses the root word with different suffixes as the end of the word n OUS- is used to name the cation with the lower of the two ionic charges n IC- is used to name the cation with the higher of the two ionic charges

42. n Example: n Fe 2+ and Fe 3+ n Name: Ferrous n Name: Ferric n What is the problem with the classical system?

43. n The classical system does not tell you the charge of the ion. n The name only tells you which cation is either larger or smaller out of the pair

44. n Few transition metals have only one ionic charge n These three elements don’t have roman numerals next to there name n Exceptions: n Ag + n Cd 2+ n Zn 2+

45. Ionic compounds n If the cation is monoatomic- Name the metal (cation) just write the name. n If the cation is polyatomic- name it n If the anion is monoatomic- name it but change the ending to -ide n If the anion is poly atomic- just name it n practice

46. Naming Binary Ionic Compounds n Write the name of CuO n Need the charge of Cu n O is -2 n copper must be +2 n Copper (II) chloride n Name CoCl 3 n Cl is -1 and there are three of them = -3 n Co must be +3 Cobalt (III) chloride

47. Naming Binary Ionic Compounds n Write the name of Cu 2 S. n Since S is -2, the Cu 2 must be +2, so each one is +1. n copper (I) sulfide n Fe 2 O 3 n Each O is -2 3 x -2 = -6 n 3 Fe must = +6, so each is +2. n iron (III) oxide

48. Ternary Ionic Compounds n Will have polyatomic ions n At least three elements (3 capital letters) n Still just name the ions n NaNO 3 n CaSO 4 n CuSO 3

49. Ternary Ionic Compounds n LiCN n Fe(OH) 3 n (NH 4 ) 2 CO 3 n NiPO 4

50. Ionic Compounds n Have to know what ions they form n off table, polyatomic, or figure it out n CaS nK2SnK2SnK2SnK2S n AlPO 4 n K 2 SO 4 n FeS n CoI 3

51. Ionic Compounds n Fe 2 (C 2 O 4 ) n MgO n MnO n KMnO 4 n NH 4 NO 3 n Hg 2 Cl 2 n Cr 2 O 3

52. Ionic Compounds n KClO 4 n NaClO 3 n YBrO 2 n Cr(ClO) 6

53. Molecular Compounds Writing names and Formulas

54. Molecules & Molecular Compounds n Elements are the building materials of the substances that make up all living and nonliving things n Only about 100 elements but there are millions of different compounds made from their atoms n Thus, naming compounds is an essential skill in chemistry

55. n In nature, only Noble Gases tend to exist as isolated atoms. n They are monatomic; that is, they consist of single atoms n Many elements found in nature are in the form of molecules n Molecule- is the smallest electrically neutral unit of a substance that still has the properties of the substance n Molecules are made up of two or more atoms that act as a unit

56. n Atoms of different elements may combine chemically to form compounds n In many compounds, the atoms combine to form molecules. n Molecular Compounds- Compounds composed of molecules n Molecular Compounds tend to have relativity low melting and boiling points n Many of these compounds thus exist as gases or liquids at room temperature.

57. Molecular compounds n made of just nonmetals n smallest piece is a molecule n can’t be held together because of opposite charges. n can’t use charges to figure out how many of each atom

58. Naming Covalent Compounds n Two words, with prefixes n Prefixes tell you how many. n mono, di, tri, tetra, penta, hexa, septa, nona, deca n First element whole name with the appropriate prefix, except mono n Second element, -ide ending with appropriate prefix n Practice

59. © 2009, Prentice-Hall, Inc. Nomenclature of Binary Compounds n The less electronegative atom is usually listed first. n A prefix is used to denote the number of atoms of each element in the compound (mono- is not used on the first element listed, however).

60. © 2009, Prentice-Hall, Inc. Nomenclature of Binary Compounds n The ending on the more electronegative element is changed to -ide. –CO 2 : carbon dioxide –CCl 4 : carbon tetrachloride

61. © 2009, Prentice-Hall, Inc. Nomenclature of Binary Compounds n If the prefix ends with a or o and the name of the element begins with a vowel, the two successive vowels are often elided into one. N 2 O 5 : dinitrogen pentoxide

62. n CO 2 n CO n CCl 4 nN2O4nN2O4nN2O4nN2O4 n XeF 6 nN4O4nN4O4nN4O4nN4O4 n P 2 O 10 Naming Covalent Compounds

63. Name These nN2OnN2OnN2OnN2O n NO 2 n Cl 2 O 7 n CBr 4 n CO 2 n BaCl 2

64. Covalent compounds n The name tells you how to write the formula n duh n Sulfur dioxide n diflourine monoxide n nitrogen trichloride n diphosphorus pentoxide

65. Write formulas for these n diphosphorus pentoxide n tetraiodide nonoxide n sulfur hexaflouride n nitrogen trioxide n Carbon tetrahydride n phosphorus trifluoride n aluminum chloride

66. More Names and formulas

67. Acids n Substances that produce H + ions when dissolved in water n All acids begin with H n Two types of acids n Oxyacids n non oxyacids

68. Naming acids n If the formula has oxygen in it n write the name of the anion, but change –ate to -ic acid –ite to -ous acid n Watch out for sulfuric and sulfurous n H 2 CrO 4 n HMnO 4 n HNO 2

69. Naming acids n If the acid doesn’t have oxygen n add the prefix hydro- n change the suffix -ide to -ic acid n HCl nH2SnH2SnH2SnH2S n HCN

71. Formulas for acids n Backwards from names n If it has hydro- in the name it has no oxygen n anion ends in -ide n No hydro, anion ends in -ate or -ite n Write anion and add enough H to balance the charges.

72. Formulas for acids n hydrofluoric acid n dichromic acid n carbonic acid n hydrophosphoric acid n hypofluorous acid n perchloric acid n phosphorous acid

73. Hydrates n Some salts trap water crystals when they form crystals n these are hydrates. n Both the name and the formula needs to indicate how many water molecules are trapped n In the name we add the word hydrate with a prefix that tells us how many water molecules

74. Hydrates n In the formula you put a dot and then write the number of molecules. Calcium chloride dihydrate = CaCl 2  2  Calcium chloride dihydrate = CaCl 2  2  Chromium (III) nitrate hexahydrate = Cr(NO 3 ) 3  6H 2 O Chromium (III) nitrate hexahydrate = Cr(NO 3 ) 3  6H 2 O