1. PowerPoint ® Lecture Slides prepared by Janice Meeking, Mount Royal College C H A P T E R Copyright © 2010 Pearson Education, Inc. 2 Chemistry Comes Alive: Part A

2. Copyright © 2010 Pearson Education, Inc. Matter Anything that has mass and occupies space States of matter: 1.Solid—definite shape and volume 2.Liquid—definite volume, changeable shape 3.Gas—changeable shape and volume

3. Copyright © 2010 Pearson Education, Inc. Energy Capacity to do work Types of energy: Kinetic—energy of motion Potential—stored energy PLAY Animation: Energy Concepts

4. Copyright © 2010 Pearson Education, Inc. Forms of Energy Chemical energy—stored in bonds of chemical substances Electrical energy—results from movement of charged particles Mechanical energy—directly involved in moving matter Radiant or electromagnetic energy—exhibits wavelike properties (i.e., visible light, ultraviolet light, and X-rays)

5. Copyright © 2010 Pearson Education, Inc. Major Elements of the Human Body Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N) About 96% of body mass

6. Copyright © 2010 Pearson Education, Inc. Lesser Elements of the Human Body About 3.9% of body mass: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)

7. Copyright © 2010 Pearson Education, Inc. Atomic Structure Neutrons No charge Protons Positive charge Electrons Negative charge

8. Copyright © 2010 Pearson Education, Inc. Figure 2.1 (a) Planetary model(b) Orbital model Helium atom 2 protons (p + ) 2 neutrons (n 0 ) 2 electrons (e – ) Helium atom 2 protons (p + ) 2 neutrons (n 0 ) 2 electrons (e – ) Nucleus ProtonNeutronElectron cloud Electron

9. Copyright © 2010 Pearson Education, Inc. Identifying Elements Atoms of different elements contain different numbers of subatomic particles Compare hydrogen, helium and lithium (next slide)

10. Copyright © 2010 Pearson Education, Inc. Figure 2.2 Proton Neutron Electron Helium (He) (2p + ; 2n 0 ; 2e – ) Lithium (Li) (3p + ; 4n 0 ; 3e – ) Hydrogen (H) (1p + ; 0n 0 ; 1e – )

11. Copyright © 2010 Pearson Education, Inc. Identifying Elements Atomic number = number of protons in nucleus Mass number = mass of the protons and neutrons Isotopes are structural variations of elements that differ in the number of neutrons they contain but always have the same number of protons.

12. Copyright © 2010 Pearson Education, Inc. Figure 2.3 Proton Neutron Electron Deuterium ( 2 H) (1p + ; 1n 0 ; 1e – ) Tritium ( 3 H) (1p + ; 2n 0 ; 1e – ) Hydrogen ( 1 H) (1p + ; 0n 0 ; 1e – )

13. Copyright © 2010 Pearson Education, Inc. Molecules and Compounds Most atoms combine chemically with other atoms to form molecules and compounds Molecule—two or more atoms bonded together (e.g., H 2 or C 6 H 12 O 6 ) Compound—two or more different kinds of atoms bonded together (e.g., C 6 H 12 O 6 )

14. Copyright © 2010 Pearson Education, Inc. Chemical Bonds Electrons occupy up to seven electron shells (energy levels) around nucleus Octet rule: Except for the first shell which is full with two electrons, atoms interact in a manner to have eight electrons in their outermost energy level (valence shell)

15. Copyright © 2010 Pearson Education, Inc. Chemically Inert Elements Stable and unreactive Outermost energy level fully occupied or contains eight electrons

16. Copyright © 2010 Pearson Education, Inc. Figure 2.5a Helium (He) (2p + ; 2n 0 ; 2e – ) Neon (Ne) (10p + ; 10n 0 ; 10e – ) 2e 8e (a) Chemically inert elements Outermost energy level (valence shell) complete

17. Copyright © 2010 Pearson Education, Inc. Chemically Reactive Elements Outermost energy level not fully occupied by electrons Tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability

18. Copyright © 2010 Pearson Education, Inc. Figure 2.5b 2e 4e 2e 8e 1e (b) Chemically reactive elements Outermost energy level (valence shell) incomplete Hydrogen (H) (1p + ; 0n 0 ; 1e – ) Carbon (C) (6p + ; 6n 0 ; 6e – ) 1e Oxygen (O) (8p + ; 8n 0 ; 8e – ) Sodium (Na) (11p + ; 12n 0 ; 11e – ) 2e 6e

19. Copyright © 2010 Pearson Education, Inc. Types of Chemical Bonds Ionic Covalent

20. Copyright © 2010 Pearson Education, Inc. Ionic Bonds Ions are formed by transfer of valence shell electrons between atoms Anions (– charge) have gained one or more electrons Cations (+ charge) have lost one or more electrons Attraction of opposite charges results in an ionic bond

21. Copyright © 2010 Pearson Education, Inc. Figure 2.6a-b Sodium atom (Na) (11p + ; 12n 0 ; 11e – ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e – ) Sodium ion (Na + )Chloride ion (Cl – ) Sodium chloride (NaCl) +– (a) Sodium gains stability by losing one electron, and chlorine becomes stable by gaining one electron. (b) After electron transfer, the oppositely charged ions formed attract each other.

22. Copyright © 2010 Pearson Education, Inc. Figure 2.6c CI – Na + (c) Large numbers of Na + and Cl – ions associate to form salt (NaCl) crystals.

23. Copyright © 2010 Pearson Education, Inc. Covalent Bonds Formed by sharing of two or more valence shell electrons Allows each atom to fill its valence shell at least part of the time

24. Copyright © 2010 Pearson Education, Inc. Figure 2.7a + Hydrogen atoms Carbon atom Molecule of methane gas (CH 4 ) Structural formula shows single bonds. (a) Formation of four single covalent bonds: carbon shares four electron pairs with four hydrogen atoms. or Resulting moleculesReacting atoms

25. Copyright © 2010 Pearson Education, Inc. Chemical Reactions Occur when chemical bonds are formed, rearranged, or broken Represented as chemical equations Chemical equations contain: Molecular formula for each reactant and product Relative amounts of reactants and products, which should balance

26. Copyright © 2010 Pearson Education, Inc. Examples of Chemical Equations H + H  H 2 (hydrogen gas) 4H + C  CH 4 (methane) (reactants)(product)

27. Copyright © 2010 Pearson Education, Inc. Rate of Chemical Reactions Rate of reaction is influenced by:  temperature   rate  particle size   rate  concentration of reactant   rate Catalysts:  rate without being chemically changed Enzymes are biological catalysts