1. Atoms, Molecules, and Ions Chapter 2 Atoms, Molecules, and Ions

2. Atoms, Molecules, and Ions Atomic Theory of Matter The theory that atoms are the fundamental building blocks of matter reemerged in the early 19th century, championed by ___(1)___

3. Atoms, Molecules, and Ions Dalton’s Postulates Each element is composed of extremely small particles called ___(2)___.

4. Atoms, Molecules, and Ions Dalton’s Postulates All atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of all other elements.

5. Atoms, Molecules, and Ions Dalton’s Postulates Atoms of an element are not changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions.

6. Atoms, Molecules, and Ions Dalton’s Postulates Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms.

7. Atoms, Molecules, and Ions Law of Constant Composition Joseph Proust (1754–1826) Also known as the law of definite proportions. The elemental composition of a pure substance never varies.

8. Atoms, Molecules, and Ions 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.

9. Atoms, Molecules, and Ions The Electron Streams of negatively charged particles were found to emanate from cathode tubes. ___(3)___ is credited with their discovery (1897).

10. Atoms, Molecules, and Ions The Electron Thompson measured the charge/mass ratio of the electron to be 1.76  10 8 coulombs/g.

11. Atoms, Molecules, and Ions Millikan Oil Drop Experiment Once the charge/mass ratio of the electron was known, determination of either the charge or the mass of an electron would yield the other.

12. Atoms, Molecules, and Ions Millikan Oil Drop Experiment ___(4)___ (University of Chicago) determined the charge on the electron in 1909.

13. Atoms, Molecules, and Ions The Atom, circa 1900: “___(5)___” model, put forward by Thompson. Positive sphere of matter with negative electrons imbedded in it.

14. Atoms, Molecules, and Ions Discovery of the Nucleus Ernest Rutherford shot  particles at a thin sheet of gold foil and observed the pattern of scatter of the particles.

15. Atoms, Molecules, and Ions The Nuclear Atom Since some particles were deflected at large angles, Thompson’s model could not be correct.

16. Atoms, Molecules, and Ions The Nuclear Atom Rutherford postulated a very small, dense ___(6)___ with the electrons around the outside of the atom. Most of the volume of the atom is ___(7)___.

17. Atoms, Molecules, and Ions Other Subatomic Particles ___(8)___ were discovered by Rutherford in 1919. ___(9)___ were discovered by James Chadwick in 1932.

18. Atoms, Molecules, and Ions Subatomic Particles ___(10)___ and ___(11)___ are the only particles that have a charge. ___(12)___ and ___(13)___ have essentially the same mass. The mass of an electron is so small we ignore it.

19. Atoms, Molecules, and Ions Symbols of Elements ___(14)___ are symbolized by one or two letters.

20. Atoms, Molecules, and Ions Atomic Number All atoms of the same element have the same number of ___(15)___: The atomic number (Z)

21. Atoms, Molecules, and Ions Atomic Mass The mass of an atom in atomic mass units (amu) is the total number of ___(16)___ and ___(17)___ in the atom.

22. Atoms, Molecules, and Ions Isotopes: Atoms of the same element with different masses. ___(18)___ have different numbers of neutrons. 11 6 C 12 6 C 13 6 C 14 6 C

23. Atoms, Molecules, and Ions Isotopes of Hydrogen

24. Atoms, Molecules, and Ions Atomic Mass Atomic and molecular masses can be measured with great accuracy with a mass spectrometer.

25. Atoms, Molecules, and Ions Average Mass Because in the real world we use large amounts of atoms and molecules, we use average masses in calculations. Average mass is calculated from the isotopes of an element weighted by their relative abundances.

26. Atoms, Molecules, and Ions Periodic Table: A systematic catalog of elements. Elements are arranged in order of ___(19)___.

27. Atoms, Molecules, and Ions Periodicity When one looks at the chemical properties of elements, one notices a repeating pattern of reactivities.

28. Atoms, Molecules, and Ions Periodic Table The rows on the periodic chart are ___(20)___. Columns are ___(21)___. Elements in the same group have similar ___(22)___ properties.

29. Atoms, Molecules, and Ions Groups These five groups are known by their names.

30. Atoms, Molecules, and Ions Periodic Table ___(23)___ are on the right side of the periodic table (with the exception of H).

31. Atoms, Molecules, and Ions Periodic Table ___(24)___ border the stair-step line (with the exception of Al and Po).

32. Atoms, Molecules, and Ions Periodic Table ___(25)___ are on the left side of the chart.

33. Atoms, Molecules, and Ions Chemical Formulas The subscript to the right of the symbol of an element tells the number of atoms of that element in one molecule of the compound.

34. Atoms, Molecules, and Ions Molecular Compounds Molecular compounds are composed of molecules and almost always contain only ___(26)___.

35. Atoms, Molecules, and Ions ___(27)___ Molecules These seven elements occur naturally as molecules containing two atoms.

36. Atoms, Molecules, and Ions Types of Formulas ___(28)___ formulas give the lowest whole-number ratio of atoms of each element in a compound. ___(29)___formulas give the exact number of atoms of each element in a compound.

37. Atoms, Molecules, and Ions Types of Formulas ___(30)___ formulas show the order in which atoms are bonded. Perspective drawings also show the three-dimensional array of atoms in a compound.

38. Atoms, Molecules, and Ions Ions When atoms lose or gain electrons, they become ___(31)___.  ___(32)___ are positive and are formed by elements on the left side of the periodic chart.  ___(33)___ are negative and are formed by elements on the right side of the periodic chart.

39. Atoms, Molecules, and Ions Ionic Bonds ___(34)___ compounds (such as NaCl) are generally formed between metals and nonmetals.

40. Atoms, Molecules, and Ions Introduction to Chemical Bonding Two types of Bonding  ___(35)___ Bonding - transfer of electrons  ___(36)___ Bonding - sharing of electrons

41. Atoms, Molecules, and Ions Bonding takes place at the highest energy level, s and p sublevels. If there are less than half the electrons between the s and p sublevels, the atom will lose the ___(37)___. If there are half or more electrons between the s and p sublevels, the atom will gain ___(38)___.

42. Atoms, Molecules, and Ions Know the trends on the periodic table for how many electrons will be gained or lost.

43. Atoms, Molecules, and Ions

44. Atoms, Molecules, and Ions Ionic Bonding Ionic bonding is the accepting or donating of electrons. Metals are ___(39)___. Nonmetals are ___(40)___. Hence, ionic bonding will occur between ___(41)___ and nonmetals.

45. Atoms, Molecules, and Ions Basic Rules of Oxidation Numbers Group 1 elements are always 1+. Group 2 elements are always 2+. Group 17 elements will be 1-. Group 16 elements will be 2-. Group 15 elements will be 3-.

46. Atoms, Molecules, and Ions Other Elements Ag = 1 + Zn = 2 + Cd = 2 + Al = 3 + Ga = 3 + In = 3 +

47. Atoms, Molecules, and Ions Other Elements with Multiple Charges Cr 2+ and Cr 3+ Fe 2+ and Fe 3+ Co 2+ and Co 3+ Ni 2+ and Ni 3+ Cu + and Cu 2+ Sn 2+ and Sn 4+ Pb 2+ and Pb 4+

48. Atoms, Molecules, and Ions Ca 2+ and S 2-  CaS Na + andCl -  NaCl Ba 2+ andN 3-  Ba 3 N 2

49. Atoms, Molecules, and Ions Writing Ions from Compounds Go with what you know.

50. Atoms, Molecules, and Ions MgCl 2  Mg 2+ andCl - CuBr 2  Cu 2+ andBr - FeCl 3  Fe 3+ andCl -

51. Atoms, Molecules, and Ions Polyatomic Ions Many atomed charged particle that acts as a single unit. Polyatomic ions have specific names. Use the names. Common polyatomic ions include:  Nitrate  Sulfate  Phosphate  Carbonate  Hydroxide  Chlorate

52. Atoms, Molecules, and Ions Other Polyatomic Ions AmmoniumNH 4 + PermanganateMnO 4 - BromateBrO 3 - Iodate I O 3 - AcetateC 2 H 3 O 2 - ChromateCrO 4 2- DichromateCr 2 O 7 2-

53. Atoms, Molecules, and Ions Changing the Oxygen Per -_____ - ate _____ - ate _____ - ite Hypo -_____ - ite _____ - ide  Move down – lose 1 oxygen each step  Move up – gain 1 oxygen each step

54. Atoms, Molecules, and Ions Ba 2+ andSO 4 2-  BaSO 4 Na + andClO 3 -  NaClO 3 Fe 2+ andCO 3 2-  FeCO 3

55. Atoms, Molecules, and Ions KNO 3  K + andNO 3 - CoSO 4  Co 2+ andSO 4 2- LiClO 3  Li + andClO 3 -

56. Atoms, Molecules, and Ions More than one of the Polyatomic Ion Needed to Balance the Charge If more than one of the polyatomic ions is needed to balance the charge, you must use parentheses ( ) around the ion. Ba(NO 3 ) 2  Ba 2+ andNO 3 -

57. Atoms, Molecules, and Ions Mg 2+ and ClO 3 -  Mg(ClO 3 ) 2 Fe 3+ and SO 4 2-  Fe 2 (SO 4 ) 3 Co 3+ and NO 3 -  Co(NO 3 ) 2

58. Atoms, Molecules, and Ions Naming Ionic Compounds Binary Ionic Compounds - Types 1 & 2  A compound that contains a positive ion (___(42)___) and a negative ion (___(43)___).  Bi- means two  Positive ion is written first, negative ion is written second in a chemical formula.

59. Atoms, Molecules, and Ions Type 1 - Binary Ionic Compound The cation of a Type 1 has only one possible charge. Name the first element (cation) as is. Name the second element (anion) as is with an ending of “-ide”. Example:CaCl 2  Calcium chloride

60. Atoms, Molecules, and Ions More Examples: Name these: NaBr-___(44)___ MgO-___(45)___ KBr-___(46)___ BaS-___(47)___

61. Atoms, Molecules, and Ions Type 2 - Binary Ionic Compounds The cation has multiple charges - copper can have a charge of 1+ or 2+. Determine which charge is being used. Use the anion as the guide. Name the element as is. Use a Roman numeral to indicate the charge being used.

62. Atoms, Molecules, and Ions Name the anion as is, using an ending of “- ide” as with Type 1 compounds. Example:CuCl 2  Copper (II) chloride  MnO 2 - ___(48)___  NiO- ___(49)___

63. Atoms, Molecules, and Ions Naming Type 1 & 2 with Polyatomic Ions Form compounds called ternary compounds - compound that contains atoms of three different elements. ___(50)___ Ion - many atomed charged particle acting as a single unit.  poly - many  atomic - atom  ion - charged particle

64. Atoms, Molecules, and Ions Type 1 & 2 Compounds with Polyatomic Ions Name the cation using the rules for Type 1 or Type 2 compounds. Name the polyatomic ion as is - use the name on the chart. Examples: NNaNO 3 -sodium nitrate BBaSO 4 -barium sulfate

65. Atoms, Molecules, and Ions Name these: LiOH- ___(51)___ Mg(NO 3 ) 2 - ___(52)___ CrCl 3 - ___(53)___ Al 2 O 3 - ___(54)___ CoBr 2 - ___(55)___ Fe 2 O 3 - ___(56)___

66. Atoms, Molecules, and Ions Covalent Bonding Covalent bonding involves the ___(57)___ of electrons between substances. Molecule - smallest neutral unit of a substance that still has the properties of the substance. Molecular formula - shows the kinds of numbers of atoms present in a molecule of a compound. Occurs between nonmetals and nonmetals.

67. Atoms, Molecules, and Ions Because these are molecules and are covalently bonded, ions are not formed - there is no transferring of electrons to form ions. Prefixes are used in naming nonmetal- nonmetal compounds.

68. Atoms, Molecules, and Ions Prefixes mono-1 di--2 tri--3 tetra--4 penta--5 hexa--6 hepta--7 octa--8 nona--9 deca--10

69. Atoms, Molecules, and Ions Prefixes: Only used for nonmetal-nonmetal compounds. Mono- is never used on the first element. Second element always has a prefix.

70. Atoms, Molecules, and Ions Naming Molecular Compounds Name the first element as is. If there is more than one of the first element, you must use a prefix. Name the second element with a prefix to indicate how many atoms there are and add the ending “- ide”. Example:  CO 2 -carbon dioxide

71. Atoms, Molecules, and Ions Name these: N 2 O- ___(58)___ PCl 3 - ___(59)___ SF 6 - ___(60)___ P 4 O 6 - ___(61)___ SO 2 - ___(62)___ NO 3 - ___(63)___ SO 4 - ___(64)___

72. Atoms, Molecules, and Ions

73. Atoms, Molecules, and Ions Naming Acids When dissolved in water, certain molecules produce hydrogen ions - H+. These substances are called ___(65)___. An acid can be viewed as a molecule with one or more H+ ions attached to an anion. The rules for naming acids depend on whether the anion contains oxygen.

74. Atoms, Molecules, and Ions

75. Atoms, Molecules, and Ions Naming Acids Identify the compound as being an acid - the first element is hydrogen (two exceptions are H 2 O and H 2 O 2 ) Find the anion on the chart. Name the anion. Following across to the name of the acid. Name the acid.

76. Atoms, Molecules, and Ions Naming Acids If you move up the chart, you gain oxygen. If you move down the chart, you lose an oxygen. Start with what you know - usually the -ate group.

77. Atoms, Molecules, and Ions Examples: HCl  The chloride ion (anion) is a single element and ends in “-ide”.  It is at the bottom of the chart.  Move across and the name of this acid is hydrochloric acid.

78. Atoms, Molecules, and Ions H 3 PO 4  The anion is phosphate.  Move across to the acids and the name of this acid is phosphoric acid. H 2 SO 4  The anion is sulfate.  Move across to the acids and the name of this acid is sulfuric acid.

79. Atoms, Molecules, and Ions HClO 2  Identified as an acid.  The anion is ClO 2 1-, which is one less oxygen than chlorate, ClO 3 1-.  Lose an oxygen, move down the chart.  Move down the chart and the name of the anion is chlorite.  Move across to the acid and the name of this acid is chlorous acid.

80. Atoms, Molecules, and Ions Name these: HNO 3 - ___(66)___ H 2 CO 3 - ___(67)___ H 2 SO 3 - ___(68)___ HNO 2 - ___(69)___ HC 2 H 3 O 2 - ___(70)___ HClO 4 - ___(71)___