1. Atomic Theory “Atom” means uncuttable. It isn’t. --but it is the smallest particle of an element

2. Early models of the atom Classical model “Plum pudding” model Solar system model

3. You need to know these people Democritus Dalton Rutherford Millikan Thomson Chadwick? Curie

4. You will need to know the contributions of… Democritus—first used the term “atom” Considered four “elements”: earth, air, fire and water (it could translate as “characteristics”) The physical shape of the “atom” gave substances their physical properties. “Atoms” are not changed in mixtures

5. You will need to know the contributions of… Dalton—modern atomic theory -all matter is made of atoms -atoms of one element are identical, atoms of different elements are different -atoms form compounds in simple whole number ratios -chemical reactions are rearrangements of atoms, the atoms are not changed -compounds with different ratios of atoms are different compounds

6. You will need to know the contributions of… Dalton—modern atomic theory -all matter is made of atoms -atoms of one element are identical, atoms of different elements are different -atoms form compounds in simple whole number ratios -chemical reactions are rearrangements of atoms, the atoms are not changed -compounds with different ratios of atoms are different compounds The law of definite proportions The law of multiple proportions

7. The mass of a proton=1 dalton It’s about the same mass as a neutron (an electron is about 1/1800 th of that mass) ~1.7 x 10 -24 g It’s also called an atomic mass unit (1amu)

8. You will need to know the contributions of… Rutherford-Gold foil experiment -showed atom is mainly empty space -mass and (+) charge in the center

9. You will need to know the contributions of… Thomson— cathode “rays” = stream of electrons He calculated the charge/mass ratio of electron

10. You will need to know the contributions of… Millikan—oil drop experiment determined the charge (& therefore the mass) of an electron

11. You will need to know the contributions of… Curie— -described radioactive decay of atoms

12. You will need to know the contributions of… Chadwick— -discovered neutrons Cloud chamber— the straight track shows that it has no charge

13. K 19 39.0983 Potassium

14. K 19 39.0983 Potassium Atomic Number = number of protons SymbolName Average atomic mass, in amu/atom

15. Atomic number and mass number Atomic number Atomic mass number # electrons

16. Atomic number and mass number Atomic number is the number of protons— determines the element Atomic mass number = #protons + #neutrons # electrons = # protons, in an atom

17. Atomic number and mass number Atomic number is the number of protons— determines the element Atomic mass number = #protons + #neutrons # electrons = # protons, in an atom An atom gains, loses, or shares electrons to form chemical bonds

18. Protons, neutrons, electrons Name Symbol Mass Charge Location Proton Neutron Electron

19. Protons, neutrons, electrons Name Symbol Mass Charge Location Proton p 1 amu +1 in nucleus Neutron n 1 amu 0 in nucleus Electron e- 0 amu -1 around nucleus, in electron cloud (about)

20. NameSymbolAtomic Number Atomic Mass Number # p# n (most likely) # e- Sulfur K 20 17

21. NameSymbolAtomic Number Atomic Mass Number # p# n (most likely) # e- Sulfur S163216 Potas- sium K1939192019 Calcium Ca204020 Chlorine Cl1735171817

22. What is an isotope?

23. “the same”“place”

24. Isotope (or nuclide) Notation K 39 19 This is potassium-39 atomic number = 19 19 protons, making it potassium, 20 neutrons,  mass number of 39

25. Isotope (or nuclide) Notation K 39 19 This is potassium-42 atomic number = 19 19 protons, making it potassium, 23 neutrons,  mass number of 42 K 42 19

26. What is an isotope? SameDifferent

27. What is an isotope? SameDifferent ElementMass Atomic numberMass number # protons# neutrons # electrons Radioactivity Ion charge Chemical properties (mostly)

28. Proton Neutron Electron (A) 23 2821 (B) 7 710 (C) 52 7154 (D) 38 4936 What is the atomic number and mass number?

29. Proton Neutron Electron (A) 23 2821 (B) 7 710 (C) 52 7154 (D) 38 4936 What is the atomic number and mass number? These aren’t atoms!

30. Proton Neutron Electron (A) 23 2821 (B) 7 710 (C) 52 7154 (D) 38 4936 Write the nuclide designation

31. (A) (B) (C) (D) Write the nuclide designation V +2 51 23 N -3 14 7 Te -2 123 52 Sr +2 87 38

32. \What is the mass number and atomic number? Br - 80 35 Ca +2 40 20 Ag + 111 47 Pu 238 94 He 3 2 Fe +2 59 26

33. How many p, n, e- in each? Br - 80 35 Ca +2 40 20 Ag + 111 47 Pu 238 94 He 3 2 Fe +2 59 26

34. Average atomic mass --A weighted average of the naturally occurring isotopes

35. Average atomic mass --A weighted average of the naturally occurring isotopes Ex: 99.63% N-14 (mass=14.003 amu/atom).37% N-15 (mass=15.000 amu/atom)

36. Average atomic mass --A weighted average of the naturally occurring isotopes Ex: 99.63% N-14 (mass=14.003 amu/atom).37% N-15 (mass=15.000 amu/atom) Avg= (.9963x14.003) +(.0037x15.000)=

37. Average atomic mass --A weighted average of the naturally occurring isotopes Ex: 99.63% N-14 (mass=14.003 amu/atom).37% N-15 (mass=15.000 amu/atom) Avg= (.9963x14.003) +(.0037x15.000)= =13.951 +.056 = 14.007 amu / atom

38. Average atomic mass What is the average atomic mass of carbon: 98.89% C-12 (12.000 amu/atom) 1.11% C-13 (13.003 amu/atom)

39. Average atomic mass What is the average atomic mass of carbon: 98.89% C-12 (12.000 amu/atom) 1.11% C-13 (13.003 amu/atom) 12.011 amu/atom

40. How common is S-32? S-32 has a mass of 31.972 amu/atom S-34 has a mass of 33.967 amu/atom (less common nuclides are ignored) The average atomic mass of sulfur is 32.060 amu/atom A) 5%B) 35%C) 65%D) 95%

41. How common is Cl-37? Cl-35 has a mass of 34.969 amu/atom Cl-37 has a mass of 36.966 amu/atom The average atomic mass of chlorine is 35.453 amu/atom A) 25%B) 50%C) 75%D)100%

42. The Periodic Table of Elements

43. Dmitry Mendeleev (Дми́трий Ива́нович Менделе́ев) Noticed physical and chemical properties repeated every seven elements (by atomic mass) Predicted the discovery of gallium and germanium

44. The Periodic Table of Elements Dmitry Mendeleev (Дми́трий Ива́нович Менделе́ев) Noticed physical and chemical properties repeated every seven elements (by atomic mass) Predicted the discovery of gallium and germanium

45. Periodic properties seen by Mendeleev: He predicted the properties of unknown elements, later discovered

46. The Periodic Table of Elements Know these features: Period Series Group Family Alkali metals Alkaline earth metals Transition elements Representative elements Halogens Noble gasses Lanthanide series Actinide series

47. A period

48. A series

49. A group or family

50. The alkali metals

51. The alkaline earth metals

52. Transition elements

53. Representative elements

54. The Halogens (salt-makers)

55. The Noble Gasses

56. The Periodic Table of Elements Boron Family Carbon Family Nitrogen Family Oxygen Family

57. The Periodic Table of Elements Actinide series Lanthanide series

58. The Periodic Table of Elements