1. The Nature of Molecules

2. Outline Describe the basic structure of an atom
Recognize the importance of electrons
Understand isotopes and radioactivity
Describe chemical bonds and why they form
Be aware of the properties of water
Understand pH and buffers

3. Matter, Molecules, Elements & Atoms
Compounds … Molecules
Elements … Atoms

4. Structure of an Atom

5. Mass Number Helium atom Mass number = 4 2 Protons 2 Neutrons 2– –
Electron
cloud
2e– + + + +
Helium atom
Nucleus 2
Protons +
Mass number = 4 2
Neutrons 2 –
Electrons

6. Mass Number Carbon atom 6 Mass number = 12 6 6 Protons Neutrons
Electron cloud
6e– + +
Nucleus
Carbon atom 6 +
Protons
Mass number = 12 6
Neutrons 6 –
Electrons

7. Atomic Number and Atomic Weight (Mass Number)

8. Periodic Table of the Elements

9. Frequency of Elements in the Earth’s Crust
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Frequency of Elements in the Earth’s Crust 1 8 H O 2 He 3 4 5 6 C 9 7 10 Li Be B F 14 N Ne 11 Si 12 13 15 Na 16 Mg Al 17 18 P S Cl Ar 26 19 20 22 Ca 21 23 24 25 Fe 27 28 29 30 31 32 33 34 35 36 K Sc Ti V Cr Mn Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 89
104
105
106
107
108
109
110 Fr Ra Ac 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 90 91 92 93 94 95 96 97 98 99
100
101
102
103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

10. Chemical Composition of the Human Body

11. Isotopes of Carbon

12. Chart of Isotopes

13. Radioactive Decay
neutron
proton
+ electron
Carbon 14
Nitrogen 14

14. Radioactivity Beta – neutron decay to loss of electron
Alpha – loss of two neutrons and two protons
Gamma – loss of energy

15. Radioactive isotope half life
C years
H years
U billion years

16. Radioactive isotope half life
Radioactive Dating
Radioactive isotope half life
C years
H years
U billion years

17. Energy from different sources
Energy (MJ/kg)
Firewood 16
Coal
9-30
Natural Gas 39
Crude oil 45
Uranium
(nuclear fission)
500,000

18. Summary of Isotopes 92 naturally occurring elements
270 stable isotopes
50 natural radioisotopes
1000’s artificial isotopes
Radioactivity
Nuclear in origin
Releases energy energy (alpha, beta, gamma)
Uses: Energy, Dating Materials, Research & Medicine

19. Energy Levels or Electron Shells
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Energy Levels or Electron Shells –
Energy released
Energy absorbed – + + M L K + K L M + +
Energy
level 3
Energy
level 2
Energy
level 1 + +
Energy
level 1
Energy
level 2
Energy
level 3

20. Energy Levels (Electron Shells)

21. Energy Levels (Electron Shells)
First electron shell holds 2 electrons
Electron
Outermost electron shell holds 8 electrons
Nucleus
Hydrogen (H)
Atomic number = 1
Carbon (C)
Atomic number = 6
Nitrogen (N)
Atomic number = 7
Oxygen (O)
Atomic number = 8

22. Periodic Table Groups & Valence Electrons
Outermost energy level Electrons increase in #
Periodic Table Groups & Valence Electrons
Energy Levels Increase
Group
Outer
Energy
Electrons

23. Ionic Bond Formation

24. Molecules Have Emergent Properties
Sodium
Chlorine
Sodium Chloride
Molecules have emergent properties.

25. Covalent Bonding

26. Covalent Bonds
Molecular
and
Structural
Formulas

27. Water Structure and Hydrogen Bonding

28. Water Structure and Hydrogen Bonding
(+) H
(–) O

29. Properties of Water Fig. 2.15(TE Art) Cohesion Adhesion
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 2.15(TE Art)
Cohesion Adhesion

30. Properties of Water
High Surface Tension

31. Properties of Water Moderates Temperature High Heat Storage
High Heat of Vaporization

32. Properties of Water
Ice Formation
Fig. 2.11b
Ice
Water

33. Solvent forms Hydration Shells
Properties of Water
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 2.17(TE Art)
Solvent forms Hydration Shells
Cl–
Cl–
Na+
Na+
Cl–
Na+
Na+
Cl–
Water
molecules
Salt
crystal

34. Table 2.1

35. Hydrogen ion concentrationpH
Hydrogen ion concentration

36. Buffers
H2O  H+ + OH-

37. END Basic Chemistry