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  1. 1. Chemistry of Life<br />Exploring Life Chapter 4<br />By M. Donohue<br />
  2. 2. Chemistry in Biology???<br />-Biology is…and all living things are made up of….MATTER!<br />The study of matter and the changes it under goesAre living things changing?<br />Chemistry<br />Anything that takes up space (V) and has mass (g)<br />Composed of one or more elements<br />Matter<br />Pure substance that cannot be broken down into other substances by chemical means“basic ingredients” of matter; examples gold, helium, oxygen, nitrogen<br />Element<br />Substance containing two OR MORE elements chemically combined in a fixed ratioexample: water, sodium chloride (aka table salt)<br />Compound<br />Smallest possible particle of an element; building block of matter<br /> -derived from Greek word “atomos” which means “indivisible”<br />Atom<br />An alternate form of an element; same # of protons, different number of electrons<br />Isotope<br />
  3. 3. Elements<br />Pure substances<br />About 25 essential elements to life<br />Trace elements<br />Make up less than 0.01% of body mass but are critical<br />-Over 100…92 naturally occurring and the rest are synthetic/man-made<br />-made up of 1 type of atom<br />Iodine<br />Iron<br />
  4. 4.
  5. 5. Some Terminology<br /><ul><li>Chemical Symbol</li></ul>One, two or three letters that represent an element on the periodic table (H, Al, Uuu)<br />First letter always capitalized, second (and third) ALWAYS lowercase<br />Doesn’t always have to be the first letter of the name (ex. Fe for Iron, K for Potassium)<br /><ul><li>Chemical Formula</li></ul>Used to represent a COMPOUND (2 or more elements bonded together)<br />Subscripts indicate the # of atoms of the preceding element inthat compound<br />If there is no subscript, it is 1 atom<br />Ex. H2O, NaCl, C6H12O6<br /><ul><li>Chemical Equation</li></ul>Representation of a chemical reaction<br />Reactants go in and products come out<br />2H2 + O2 2 H2O<br />H2CO3(aq)  ->   H2O(l) + CO2(g)<br />
  6. 6. Physical Change/properties<br />Color, shape, texture, amount<br />The actual make-up of matter/substance does NOT change<br />Examples<br />Ripping a piece of paper<br />Painting a wall<br />When two substances are combined to create a new substance with new properties different from those that made it up…Combo of different elements<br />Examples<br />Water H2O<br />Sodium chloride NaCl<br />Chemical change/properties<br />Compounds<br />When 2 or more elements are chemically combined in fixed ratios making a new substance with new properties<br />
  7. 7. Atomic Theory<br />Dalton’s Atomic Theory<br />1) All matter is made of atoms that are indivisible and indestructible.<br />2) All atoms of a given element are identical in mass and properties<br />3) Compounds are formed by a combination of two or more different kinds of atoms.<br />4) A chemical reaction is a rearrangement of atoms. <br />
  8. 8. Structure of an Atom<br />-smallest unit of matter that retains properties of element<br />-Atom has an electric charge of zero (all positives equal negatives)<br />
  9. 9. <ul><li>Atomic Number= Number of protons
  10. 10. You can find this on the periodic table
  11. 11. (smaller # by the element…goes in numerical order)
  12. 12. In a neutral atom: (charge of 0)</li></ul> # of p+=# of e--<br /><ul><li>Mass Number = the number of protons and neutrons in the nucleus of an atom
  13. 13. (bigger # on PT)
  14. 14. # of neutrons= mass# - atomic#</li></li></ul><li>Periodic Table Terminology<br /><ul><li>Rows (go left to right) are called Periods
  15. 15. Columns (that go up and down) are called GROUPS or FAMILIES
  16. 16. Number your columns…1(H),2, skip all the ones that drop down, 3 (B), 4, 5, 6, 7, 8
  17. 17. Families share similar characteristics</li></ul>Groups of friends have similar interests, act the same<br />Elements in the same group/family have the SAME CHEMICAL PROPERTIES<br />They react the same!!<br />
  18. 18. <ul><li>Opposites attract…+protons attract -electrons and hold them in place in the electron cloud
  19. 19. Electrons are arranged in “orbitals” around the nucleus
  20. 20. First orbital/ring has a maximum capacity for 2 electrons
  21. 21. Each ring after has a MAX Capacity for 8 electrons
  22. 22. VALENCE electrons are the ones in the outer most ring!
  23. 23. Columns of the periodic table tell you how many valence electrons there are</li></ul>The ELECTRON Cloud<br />
  24. 24. So…what info about an <br />atom do we get from <br />the Periodic Table???<br /><ul><li># of Protons
  25. 25. # of Electrons
  26. 26. # of neutrons
  27. 27. Mass #
  28. 28. Chemical Reactivity
  29. 29. More on this later</li></li></ul><li>1. gold2.potassium3.xenon4. germanium5. Tungsten<br />For each of the following, determine:<br /> a. Atomic Number<br /> b. Mass Number<br /> c. Number of Protons<br /> d. Number of Electrons<br /> e. Number of neutrons<br />PRACTICE!!<br />
  30. 30. Chemical Reactivity<br />Ability of one substance to combine with another substance and form a new substance<br />***ELECTRONS*** determine chemical reactivity<br /><ul><li>With the EXCEPTION of He and H (why do you think they are by themselves), all atoms want to try and have 8 Valence (outer) electrons
  31. 31. H and He only need 2 to be happy
  32. 32. 8 valence e- = 
  33. 33. 2 v.e. =  for H and He
  34. 34. Time to play..the RINGS!!!</li></li></ul><li>