Entry Task: Oct 5 th Friday

1. Entry Task: Oct 5th Friday Question: 1. What physical characteristics do these two models of an atom have in common? 2. How do the two models differ? Peach CC-cookie

2. Agenda: • Sign off on Ch. 4 sec. 1-3 ws • Notes on protons, neutrons & electrons and Isotopes • HW: Isotope worksheet

5. Protons  Electrons  Protons  Electrons 

13. I can… • Explain the relationship between proton, electron and neutrons with atomic number and atomic mass. • Define an isotope and explain why atomic masses are not whole numbers

14. Atomic Number • Is the number of protons in the nucleus. • Atomic # = # of protons = # of electrons

15. Mass Number • Is the sum of the number of protons + neutrons in the nucleus of an atom. 6 C 12.001 # of protons # of protons # neutron

16. Using a Periodic Table 2 2 2 4 2 11 11 12 23 11 16 16 16 32 16 47 47 61 108 47 94 94 150 244 94

17. You Try… Zirconium 40 40 40 130 Cesium 55 55 Mercury 80 80 121 73 Arsenic 33 33

18. Isotopes

19. Lets say that massed and recorded 100 pennies. And the following is the data that you recorded.

20. 1994 U.S. Pennies 90 of the pennies have a mass of 2.63 grams 5 of the pennies have a mass of 2.60 grams 5 of the pennies have a mass of 2.67 grams What can you deduce from this information?

21. The information gained is: 90% of all 1994 pennies will have a mass of 2.63 grams 5% of all 1994 pennies have less mass of 2.60 grams 5% of all 1994 pennies have more mass of 2.67 grams 10% of the pennies have more or less metal in them.

22. What are isotopes? Isotopes are the same as the pennies but with a particular element • Isotopes are elements with the same number of protons and electrons but the number of neutrons differ from the average amount. OR It’s an atom that has more or less the average number of neutrons in the nucleus of an atom

23. How can scientist “weigh” an atom? Scientist can’t “weigh” an atom. But they can determine the mass of an atom by how it behaves. So how do they do it… lets look at an analogy.

24. Imagine a race track that bends at a 90° angle. Take 3 cars- all going the same speed What can be assumed by the weight/mass of the pink car? Too heavy to make the turn What can be assumed by the weight/mass of the blue car? Too light to make the turn What can be assumed by the weight/mass of the orange car? Its mass was enough to make the turn.

25. Scientist use a mass spectrometer • It is the “race track” for atoms. • The atoms are the “cars”

27. Atomic weight measurements From the mass spectrometer, clearly there are more neon atoms with a mass of 20. The next is 22 and lastly is 21.

28. How do you know if its an isotope The periodic table records the AVERAGE atomic mass. If a given atomic mass for a particular element is NOT on the periodic table- You have an ISOTOPE

29. Sulfur-34 Sulfur is the element The atomic mass is 34 Look on periodic table- its mass is listed as 32 Is it an isotope? Yes- it is an isotope How many protons, electrons and neutrons does this atom have? 16+ 16- 18ø

30. 3 8 3 3 5 31 67 31 31 36 81 81 120 81 201 82 82 82 208 126