1. When Atoms Change…

2. What we KNOW… Atoms on the periodic table are neutral. Atoms are neutral because they have the same number of protons as electrons. protons have a positive charge. neutrons have no charge. electrons have a negative charge.

3. What we Also need to KNOW… The identity of an atom is determined ONLY by the number of protons. For example… If I tell you there is an atom with 3 protons… you know it’s a Lithium atom. What about 8 protons, 13 protons, 79 protons???

4. What happens if the number of neutrons change??? If an atom gains Neutrons… 1. The mass increases by 1 for every neutron added. 2. The charge remains neutral. (Neutrons don’t have a charge.) 3. The number of protons and electrons stay the same. If an atom loses Neutrons… 1.The mass decreases by 1 for every neutron taken away. 2.The charge remains neutral. (Neutrons don’t have a charge.) 3.The number of protons and electrons stay the same.

5. What happens if the number of neutrons change??? If an atom gains Neutrons… 1. The mass increases by 1 for every neutron added. 2. The charge remains neutral. (Neutrons don’t have a charge.) 3. The number of protons and electrons stay the same. If an atom loses Neutrons… 1.The mass decreases by 1 for every neutron taken away. 2.The charge remains neutral. (Neutrons don’t have a charge.) 3.The number of protons and electrons stay the same.

6. The atom is now called an ISOTOPE! When atoms gain or lose neutrons !

7. ISOTOPE EXAMPLE Hydrogen Atom Has a mass of 1 and an atomic number of 1 Hydrogen Isotope Has a mass of 2 and an atomic number of 1

8. ISOTOPE NOTATION We communicate that we have an isotope by using the Atomic Symbol of the isotope followed by the “NEW” mass number. ISOTOPE NOTATION Li-7 Ex: An Isotope of Lithium is: Li - 6

9. Isotope INVENTORY Completing a particle inventory for an Isotope is almost the same as the neutral atom EXCEPT we USE THE “NEW” MASS NUMBER to calculate neutrons. Ex: Li-6 3p+ (since it’s Lithium!!!) 3e- (since they are still equal to p+) 3n

10. Isotope Practice Ca atom has a mass of 40. The isotopes for Ca are: Ca-42, Ca-43,Ca-44, Ca-46, & Ca-48. 1.) How many neutrons are in a Ca atom and each of its isotopes? 2.) What are the differences and similarities between the Ca atom and its isotopes?

11. Isotope Practice Ca atom has a mass of 40. (atomic # =20) The isotopes for Ca have masses of 42,43,44,46, & 48. 1.) How many neutrons are in a Ca atom and each of its isotopes? (Ca ATOM: 40 – 20 = 20n) (ISOTOPES: 42-20=22n, 43-20=23n, 44-20=24n, 46-20=26n, 48-20=28n) 2.) What are the differences and similarities between the Ca atom and its isotopes? SimilaritiesDifferences (All have 20 p+ all have 20 e- all neutral all are Calcium) (The # of neutrons is different, masses are all different.)

12. Everyone gets 7 blue, 7 red, 7 yellow Red = Protons Blue = Neutrons Yellow = Electrons Play 1-5 marbles per turn. Number of neutrons and protons Number of protons and electrons Subtract the two to find the number of neutrons The Atom Building Game

13. Everyday Uses of Isotopes Smoke Detectors and Americium-241 What most consumers don't know is that many of these units contain a small amount of americium-241. By utilizing the radioactive properties of this material, smoke from a fire can be detected at a very early stage. This early warning capability has saved many lives. In fact, studies have shown that 80% of fire injuries and 80% of fire fatalities occur in homes without smoke detectors.

14. Carbon-14 Dating Recalling that all biologic organisms contain a given concentration of carbon-14, we can use this information to help solve questions about when the organism died. When an organism dies it has a specific ratio by mass of carbon-14 to carbon-12 incorporated in the cells of it's body. At the moment of death, no new carbon-14 containing molecules are metabolized, therefore the ratio is at a maximum. After death, the carbon-14 to carbon-12 ratio begins to decrease because carbon-14 is decaying away at a constant and predictable rate. Remembering that the half-life of carbon-14 is 5700 years, then after 5700 years half as much carbon-14 remains within the organism.

15. Food Irradiation Food irradiated by exposing it to the gamma rays of a radioisotope -- one that is widely used is cobalt-60. The gamma rays pass through the food to destroy many disease-causing bacteria as well as those that cause food to spoil. It’s not strong enough to change the quality, flavor or texture of the food. The food never comes in contact with the radioisotope and is never at risk of becoming radioactive!

16. Reviewing Isotopes What are isotopes gaining or losing? Here is an Atom of Oxygen (how many neutrons?) Atomic Mass=16 These are isotopes of Oxygen O-17O-18 So…How many neutrons does each isotope of Oxygen NOW have? 8 neutrons Neutrons! 10N9N

17. Isotope Practice 1.)How many neutrons are in each of Zinc’s isotopes? Zn-65 Zn-64____ Zn-67_____ Zn-70____ 2.) What are the differences and similarities between the Zn atom and its isotopes? Set-up a “T” Chart

18. Isotope Practice 1.)How many neutrons are in each of Zinc’s isotopes? Zn-65 Zn-64____ Zn-67_____ Zn-70____ 2.) What are the differences and similarities between the Zn atom and its isotopes? 344037 SimilaritiesDifferences All have 30 p+ all have 30 e- all neutral all are Zinc # of neutrons is different masses are all different

19. Isotope Warm up 1.)How many neutrons are in each of Strontium’s isotopes? Sr-84____ Sr-86_____ Sr-87____ Answers: Sr-84 46 Sr-86 48 Sr-87 49

20. Quiz Quick Isotopes gain or lose… A.electrons B.protons C.neutrons D.nuclei

21. When an atom gains neutrons, its charge changes. A.True B.False

22. When an atom gains neutrons, the number of protons and electrons do not change. A.True B.False

23. The only subatomic particles that never change are… A.Valance electrons B.Protons C.Electrons D.Neutrons

24. What happens if the number of electrons change??? If an atom gains electrons… 1. The charge becomes negative. (There are more negative e- than positive p+ now!) 2. The mass stays the same (electron’s mass = 0). 3. The number of protons and neutrons stays the same. If an atom loses electrons… 1.The charge becomes positive. (There are less negative e- than positive p+ now!) 2.The mass stays the same (electron’s mass =0). 3. The number of protons and neutrons stays the same.

25. What happens if the number of electrons change??? If an atom gains electrons… 1. The charge becomes negative. (There are more negative e- than positive p+ now!) 2. The mass stays the same (electron’s mass = 0). 3. The number of protons and neutrons stays the same. If an atom loses electrons… 1.The charge becomes positive. (There are less negative e- than positive p+ now!) 2.The mass stays the same (electron’s mass =0). 3. The number of protons and neutrons stays the same.

26. The atom is now called an ION!!! When atoms gain or lose electrons! *Ions are charged particles! Ions form so that unstable atoms can bond with other unstable elements to become a stable substance!

27. Charged Ions Anion (-) Negatively charged ion. Cation (+) Positively charged ion

28. Quick Quiz If an atom loses electrons, its mass changes? A.True B.False

29. Ions gain or lose… A.isotopes B.protons C.neutrons D.electrons

30. Gaining electrons causes atoms to… A.Gain more mass B.Have a charge C.Stay neutral D.Lose mass

31. ION EXAMPLE H+ is a positive hydrogen ION H: Is the neutral hydrogen atom H- : is a negative hydrogen ION

32. Ion Practice Na Be I Ca Sb S P C Na +1 Be +2 I -1 Ca +2 Sb -3 S -2 P -3 C +/-4

33. Ion Worksheet Answers Li +1 Br -1 Mg +2 B +3 F -1 N -3 Cl -1 K +1 Ba +2 Te -2 Sn -4 As -3 Si +/-4 O -2 Al +3

34. Ion Worksheet Coloring Li +1 Br -1 Mg +2 B +3 F -1 N -3 Cl -1 K +1 Ba +2 Te -2 Sn -4 As -3 Si +/-4 O -2 Al +3

35. What patterns did you notice from coloring your ions on the periodic table? *hint* there is more than one! The families where the same color. The families had the same ionic charge. Metals have a positive charge. Non-metals have a negative charge. Metals lose electrons. Non-metals gain electrons.

36. Practice Draw the Bohr models for the following elements and find the ionic charges for each. Rb Sr Bi Rb Sr Bi -3 +2 +1

37. How is the neutral (no charge) atom Se and it’s isotope Se-78 similar and different? (Set up a “T” chart) Similar Same element Same # of protons Same # of electrons Same charges Different Different masses Different # of neutrons

38. How are isotopes and ions similar and different? (setup a T chart) (hint* think about particles, masses and charges) Similarities Same number of protons only! Differences Diff Masses Diff Number of neutrons Diff Charges Diff Number of electrons

39. Practice Draw the Bohr models for the following elements and find the ionic charges for each. Ga Sr Pb Ga Sr Pb -4 +2 -5

40. Patterns on the Periodic Table

41. +1 +2 +3 +/-4 -3-2 0 Ionic Charges

42. Valence Electrons

43. 1 Shell 3 Shells 4 Shells 5 Shells 6 Shells 7 Shells 2 Shells Period 1 Period 2 Period 4 Period 3 Period 5 Period 6 Period 7 Energy Shells of Atoms

44. Families/Groups have a lot in common … We now know that elements in a group all have the same # of valence e-. We also now know they all form ions with the same charge. But…there are a lot of other properties that elements in a family also share! Such as…Atomic Width, Ionization Energy, Electronegativity and reactivity.

45. Atomic Radius (Width ) Atomic radius is simply the radius (width) of the atom, an indication of the atom's volume. Periods - atomic radius decreases as you go from left to right across a period. Why? Stronger attractive forces in atoms (as you go from left to right) between the opposite charges in the nucleus and electron cloud cause the atom to be 'sucked' together a little tighter. Largest atomic species are those found in the SW corner of the periodic table.

47. Atomic Radius (Width) Groups - atomic radius increases as you go down a group. Why? There is a significant jump in the size of the nucleus (protons + neutrons) each time you move from period to period down a group. Additionally, new energy levels of elections clouds are added to the atom as you move from period to period down a group, making the each atom significantly more massive, both is mass and volume.

49. Ionization Energy Ionization energy is the amount of energy required to remove the outmost electron. It is closely related to electronegativity. Group - ionization energy decreases as you go down a group. Why? The shielding affect makes it easier to remove the outer most electrons from those atoms that have many electrons (those near the bottom of the chart).

50. Electronegativity Electronegativity is an atom's 'desire' to grab another atom's electrons. Period - electronegativity increases as you go from left to right across a period. Why? Elements on the left of the period table have 1 - 2 valence electrons and would rather give those few valence electrons away, as a result, they have low electronegativity. Elements on the right side of the period table only need a few electrons, so they have strong desire to grab another atom's electrons.

51. Electronegativity Electronegativity is an atom's 'desire' to grab another atom's electrons. Group - electronegativity decreases as you go down a group. Why? Elements near the top of the period table have few electrons to begin with; every electron is a big deal. They have a stronger desire to acquire more electrons. Elements near the bottom of the chart have so many electrons that loosing or acquiring an electron is not as big a deal.

52. Reactivity Elements become more reactive as you go down a group on the left side And more reactive as you go up a group on the right side! Reactivity refers to how likely or vigorously an atom is to react with other substances. Based on this, where are the most reactive elements found on the periodic table? Bottom left corner (Fr) and top right corner (F)

53. What are (7) things you can now predict about the element Iodine (I), based on where it is located on the Periodic Table? 1. It has 7 valence electrons 2. It has 5 energy rings/shells 3. It is a non-metal 4. It’s gaining 1 electron 5. It’s ionic charge is -1 6. Less reactive than Br and Cl 7. But it’s more massive than Br and Cl

54. Properties of Non-metals No luster Brittle Not ductile Not malleable (dull) (breaks easily)

55. What can you now tell me about the element Nitrogen (N) and Potassium (K), based on where they are located on the Periodic Table? ( think about shells, valence e’s, charges, metal/non-metal, gaining/losing e’s) Potassium 1 valence electron It has 4 energy rings It is a metal It’s losing 1 electron It’s ionic charge is +1 Nitrogen 5 valence electrons It has 2 energy rings It is a non-metal It’s gaining 2 electrons It’s ionic charge is -3

56. You are the bus driver. At your first stop, you pick up 29 people. On your second stop, 18 of those 29 people get off, and at the same time 10 new passengers arrive. At your next stop, 3 of those 10 passengers get off, and 13 new passengers come on. On your fourth stop 4 of the remaining 10 passengers get off, 6 of those new 13 passengers get off as well, then 17 new passengers get on. What is the color of the bus driver's eyes?