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What is a Symbol?

What is a Symbol?. Elements and Chemical Symbols. Chemical Symbols / Element Names. H Hydrogen. Cl Chlorine. C Carbon. O Oxygen. Co Cobalt. Writing Chemical Symbols. 1. First letter is capitalized. 2. Second letter is lower case. 3. NO period at the end.

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What is a Symbol?

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  1. What is a Symbol?

  2. Elements and Chemical Symbols Chemical Symbols / Element Names H Hydrogen Cl Chlorine C Carbon O Oxygen Co Cobalt

  3. Writing Chemical Symbols 1. First letter is capitalized 2. Second letter is lower case 3. NO period at the end H Cl O Hg Fe Sn C He

  4. Does it really matter? Co or CO

  5. Co • Cobalt-60, extensively used as a tracer and a radiotherapeutic http://members.tripod.com/duebills/27.html

  6. Required in soils • growing animal feed Co

  7. Co • Alloys for metals used in jet turbines

  8. CO Kills 200 People in United States http://www.cpsc.gov/cpscpub/pubs/466.html

  9. CO Produced by Incomplete Burning of Fossil Fuels

  10. oxygen carbon CO Compound • carbon monoxide • Colorless • Odorless • Poisonous gas

  11. Think before you write a Element’s Symbol

  12. Elements are substances: • That cannot be broken down • into other substances • Made of atoms with the same • number of protons in the nucleus

  13. Elements are listed on the Period Table

  14. Use your copy of the Periodic Table of Element Correctly write the symbol for: C • Carbon • Nitrogen • Oxygen • Iron • Chlorine N O Fe Cl

  15. Atomic Number Number of Protons in every Atom of that Element

  16. What is the name of the element with the following number of protons? Helium • 2 • 6 • 8 • 11 • 47 Carbon Use the Periodic Table Oxygen Sodium Silver

  17. Atomic Mass Number Protons + Neutrons To calculate # of neutrons 1. Round the Mass Number to the nearest whole number Round to 28

  18. Atomic Mass Number Protons + Neutrons Calculate # of neutrons 2. Subtract Atomic Number From Mass Number 28 (Mass #) -14(Atomic #)14 Neutrons

  19. Protons + electrical charge + Neutron No electrical charge Electrons - electrical charge -

  20. Neutral Atoms (Atoms without Electric Charge) • Have equal numbers of: • Protons (+ charges) • Electrons (- charges)

  21. How many electrons? 1 proton 9 protons 99 protons 1 electron 9 electrons 99 electrons

  22. Use the Periodic Table and Math Skills to fill in the blanks

  23. # protons is the atomic # protons + neutrons = mass # #electrons = # protons

  24. Compounds 2 or More Elements Chemically Combined 2-H: 1-O Hydrogen Hydrogen Oxygen

  25. H H Ratio 2:1 1 is not shown O H2O Formulas use element symbols with subscript numbers Water

  26. Change the ratio Change the substance 2:2 Hydrogen Peroxide H2O2 Subscript numbers http://www.wonderquest.com/images/2003-08-08-peroxide.jpg

  27. No subscripts?? NaCl Salt 1Na 1Cl 2 How many elements?

  28. C6H12O6 Sugar How many elements? 3 How many hydrogen atoms? 12

  29. Use your Periodic Table √Check your understanding

  30. 1. The symbol for carbon is – A Ca B c C CA D C

  31. 1. The symbol for carbon is – A Ca Incorrect: Symbol for calcium B c Incorrect: 1st letter is always a capital

  32. 1. The symbol for carbon is – C CA Incorrect: C is carbon There is no element with the symbol A D C Correct: Capital C is the symbol for carbon

  33. 2. How many protons are in an atom of sodium? A 11 B 12 C 23 D 34

  34. 2. How many protons are in an atom of sodium? A 11 B 12 Correct: atomic # is 11 Incorrect: 12 is the number of neutrons

  35. 2. How many protons are in an atom of sodium? C 23 D 34 Incorrect: 23 is the mass number Incorrect: No subatomic particle # is found by adding the atomic and mass numbers

  36. How many neutrons are there, • if the mass number is 1 and • the atomic number is 1? A 3 B 2 C 1 D 0

  37. How many neutrons are there, • if the mass number is 1 and • the atomic number is 1? A 3 B 2 Incorrect: There may be more or less neutrons than protons Incorrect: No subatomic particle # is found by adding the atomic and mass numbers

  38. How many neutrons are there, • if the mass number is 1 and • the atomic number is 1? Incorrect: There is 1 proton & 1 electron C 1 D 0 Correct: 1-1 = 0

  39. How many electrons are in • an atom of Cl? A 17 B 18 C 35 D 0

  40. How many electrons are in • an atom of Cl? Correct: There are 17 + charges, so there are17 - charges A 17 B 18 Incorrect: 35-17 = number of neutrons

  41. How many electrons are in • an atom of Cl? C 35 D 0 Incorrect: Mass # is the sum of protons & neutrons Incorrect: All neutral atoms have at least 1 electron

  42. Which of the following is • a formula? A H B O C H2O D h2o

  43. Which of the following is • a formula? A H B O Incorrect: Symbol for hydrogen Incorrect: Symbol for oxygen

  44. Which of the following is • a formula? Correct: There are 2Elements The ratio is 2:1 C H2O D h2o Incorrect: 1st letter is a capital 2 is not written as a subscript

  45. How many elements are in • baking soda, NaHCO3 ? A 6 B 5 C 4 D 3

  46. How many elements are in • baking soda, NaHCO3 ? Incorrect: There are 6 atoms A 6 B 5 Incorrect: The lower case “a” is part of the symbol for sodium

  47. How many elements are in • baking soda,NaHCO3 ? C 4 D 3 Correct: 4 elements: sodium, hydrogen, carbon, oxygen Incorrect: 3 is the subscript for oxygen

  48. Graphics Microsoft Clip Art Microsoft Office Online http://www.wonderquest.com/images/2003-08-08-peroxide.jpg http://www.cpsc.gov/cpscpub/pubs/466.html agenthttp://members.tripod.com/duebills/27.html http://www.wonderquest.com/images/2003-08-08-peroxide.jpg http://www.tea.state.tx.us/student.assessment/taks/booklets/science/g8e.pdf

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