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Honors Biology Chapter 2

Honors Biology Chapter 2. Chemistry. Are you wondering why we are learning chemistry in biology class?. All of our cells are made of chemical compounds. All the activities of our bodies work on chemical reactions. All of our body’s reactions use water.

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Honors Biology Chapter 2

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  1. Honors Biology Chapter 2 Chemistry

  2. Are you wondering why we are learning chemistry in biology class? • All of our cells are made of chemical compounds. • All the activities of our bodies work on chemical reactions. • All of our body’s reactions use water. Such as neurotransmitters affecting neurons

  3. ELEMENTS • Substance that cannot be broken down to other substances by ordinary chemical means (heating, adding an acid…)

  4. COMPOUNDS • Substance of two or more different atoms chemically combined in a fixed ratio • EXAMPLES: CO2 • H2SO4 • H2O • CO • How is a compound written differently than an element? • More than one kind of element (more than one capital letter). • NOTE: H2 is not a compound – its an element • (Only one kind of element) Subscripts (tell how many atoms there are)

  5. Formula • Formula is the abbreviation for a compound. • CO2 H2SO4 H2O • Carbon dioxide sulfuric acid water • What rules seem to apply to writing a formula? • Capital letters for elements • Subscript number behind and just below the line of what element it represents

  6. Which are compounds? • Na N H2 NO2 H2O Why? • NO2 • H2O • 2 or more different elements chemically joined (2+ diff. capital letters)

  7. Can you figure out the difference between a mixture and a compound? • A mixtureis two or more elements (or compounds) NOT chemically joined. • A compound is two or more atoms chemically joined. • Do Worksheet: Elements, Compounds, Mixtures

  8. Atoms are made of protons, neutrons, electrons • Do you know what these particles are?

  9. Answers: • Do you know what these particles are? Protons Neutrons Electrons

  10. Basic Atomic Structure Youtube (1:57)

  11. What is the charge of each subatomic particle? • Proton Neutron Electron • + O _ • positive none negative

  12. What is the relative size? • Proton neutron electron • 1 amu 1 amu ~1/1836 amu • AMU = atomic mass unit = 1/12 CARBON ATOM • (standard)

  13. Neutral Atoms (no charge)(as seen on the periodic table) • 39 Mass Number p + n K Symbol • 19 Atomic Number p • (electrons = number of protons) • Neutral if negative charges = positive ) • n=mass no. – at.no.

  14. How can you tell the mass number and atomic number?

  15. Atomic Number In order Identify element by its number of protons Mass Number A decimal (average of masses of all isotopes of that element) When looking on the periodic table…

  16. Why is the mass number a decimal?Average of the Isotopes of Carbon • What is the mass number decimal? • 12.011 • What would you round it to? • 12

  17. What is the atomic number of? • Silicon fluorine sodium WHY? • 14 9 11 • Number in succession (not a decimal) • Number of protons

  18. What is the mass number of…? • Carbon nitrogen hydrogen • WHY? • 12 14 1 • Decimal number on periodic table • Not other number in succession • Number of p + n

  19. How do you find the number of…? • Protonselectrons neutrons Atomic atomic mass number numbernumber minus atomic no. (if neutral)

  20. How many? • Protons electrons neutrons • Carbon 6 6 6 • Chlorine • 17 17 18

  21. What is the atomic number?Mass Number? • Number of p? • Number of e-? • Number of n?

  22. Do Atomic Mass and Atomic Number WORKSHEET • Collaborate with your partner next to you, then we’ll see what’s right.

  23. ISOTOPES INTRO • Isotopes (Virtual School) (2:51) • Watch the video and list what facts you learned about isotopes. • No, not about the Albuquerque Isotopes

  24. Isotope • Atoms that differ in number of neutrons • Also differ in mass number(since it is p + n) • But all have the same number of protons

  25. Isotope Examples • What are isotopes? (7:56)

  26. Which is the most common isotope of Li? (check the periodic table)

  27. Why is the Mass Number a Decimal? • Finding the Average Atomic Mass (2:55) • Watch this and find out how…

  28. How do you write chemical notation for isotopes?

  29. 2.4 Radioactive Isotopes • An isotope that decays spontaneously to emit (give off) particles or energy until it is stable • Here a radioisotope is used to examine a thyroid gland • Radioactive Tracers in Medicine (3:57)

  30. Radioactive Decay Examples

  31. Uses of Radioisotopes • C-14 dating (can date living things up to 6,000 years old) Carbon Dating (2:00 mins) • Technetium 99 Radioisotope (2:58) • Nuclear Medicine: What to expect (2:46 mins) • Bozeman Biology Radioactive Dating (9 mins) • Carbon-14 Dating (2 mins) PET SCAN: detect tumors, weak spots in arteries Highlight parts of the body for diagnosis Thyroid tumor

  32. Uses of Radioisotopes • Iodine-131 PIB molecule to treat thyroid cancer detect Alzheimers PET scan

  33. Negative Effects of Nuclear Radiation • Chernobyl Nuclear Plant Accident

  34. Negative Effects of Radon • Radon, a radioactive gas, causes lung cancer • Found in regions containing uranium

  35. 2.5-2.7 Chemical Bonds

  36. Ion • Charged atom • Differs in number of electrons • 39 Same mass number K+ means lost one electron • 19 Same atomic number

  37. ION • Charged atom • Na+ (has lost one electron) • O-2 (has gained two electrons) • Shown with superscript +/- and number on upper right • (can omit number if a “1”) • What's and Ion? Youtube (6:52)

  38. Ions form by gaining or losing electrons

  39. O-2 has gained two electrons Na has lost an e- so it is Na+1

  40. Cation Anion Negative ion Cl- O-2 gained electrons • Positive ion • Na+ • Mg+2 • Lost electrons

  41. If one electron is… • Lost what charge will the ion have? • +1 11p+ 11 e- 11p+ 10e-

  42. Which are ions? • Cl O-2 Na+1 N2 Why? • O-2 Na+1 • Charged atoms (lost or gained electrons) • show charges as superscripts

  43. Valence Electrons • Outer shell electrons • Determines the bonding capacity of an atom

  44. How do electrons arrange themselves in an atom… • In the outer electron shells (energy levels)? • They are full with 2, 8, 8 • Fill inner shell first, then go to next shell out (Outermost shell has the greatest energy) Can you see any pattern how the e- arrange themselves?

  45. Get kinda complicated beyond 2,8,8…so that’s all we’ll do for now!

  46. Which electrons determine… • The chemical properties of the atom? • Outermost shell

  47. If one electron is gained… • What charge will the ion have? • -1

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