1. Ch. 3 & Nuclear Chemistry
Whiteboard Review!

2. What is the name of this device?
Which scientist used this device?

3. Cathode Ray tube
JJ Thomson

4. α β List the two symbols that scientists use to represent a(n)…
Alpha particle?
Beta particle? α β

5. Complete the table for the main subatomic particles.
Relative Charge
Mass Number
Location in atom
Proton +1 1
nucleus
Neutron
Electron -1
Outside nucleus

6. Complete the table for the main subatomic particles.
Relative Charge
Mass Number
Location in atom
Proton +1 1
nucleus
Neutron
Electron -1
Outside nucleus

7. What does the atomic number represent?
The number of protons in the nucleus of each atom of that element

8. Write the isotope symbol and hyphen notation for the name of the isotope that has 2 protons and 2 neutrons.
Helium He 2

9. Find how many half-lives it takes to decay to 25 g.
Thorium-230 has a half life of 8000 years. How long will it take a 100 g sample of Th-230 to decay to 25 g?
Find how many half-lives it takes to decay to 25 g.
100 → 50 → 25
2 half-lives.
2 x 8000 = 16,000 years

10. What is the most common isotope of Zinc? Use isotope notation.

11. Ra He + Rn I e- + Xe Radium-222 (Ra, alpha decay)
Iodine-131 (beta decay) Ra
222 88 He 4 2 + Rn
218 86 I
131 53 e- -1 + Xe 54

12. A student finds that 15. 20g of nitrogen will react with 17. 37g, 34
A student finds that 15.20g of nitrogen will react with 17.37g, 34.74g, or 43.43g of oxygen to form three different compounds. This is an example of which law?
Law of Multiple Proportions

13. Calculate the average atomic mass of argon to 2 decimal places give the following isotopes: MUST SHOW YOUR WORK!!!
Argon-36 (35.97amu; 0.337%)
Argon-38 (37.96amu; 0.063%)
Argon-40 (39.96amu; %)
39.95 amu

14. What kind of nuclear reaction takes place in a nuclear power plant?
Fission!

15. What is the smallest particle of an element that retains the chemical properties of that element?
Atom!

16. Write the equation for the radioactive decay of the following elements:
Uranium-234 (U, alpha decay)
Bismuth-214 (Bi, beta decay) U
234 92 He 4 2 + Th
230 90 Bi
214 83 e- -1 + Po 84

17. What experiment did Millikan do and what was one of his conclusions?
Oil Drop Experiment
Determined the mass of an electron (1/2000th the mass of H atom)
Determined the charge on the electron (negative)

18. How many neutrons would a stable isotope of Tin (Sn) have?
58-75

19. Naturally occurring boron is 80. 20% boron-11 (11. 01amu) and 19
Naturally occurring boron is 80.20% boron-11 (11.01amu) and 19.80% of another isotope. The average atomic mass of boron is 10.81amu. What must the atomic mass of the second isotope be? MUST SHOW YOUR WORK!!!
10.01 amu

20. Define isotope
Atoms of the same element that have different masses

21. Write a radioactive decay equation that will produce/make magnesium Using alpha decay - Using beta decay Si 28 14 He 4 2 + Mg 24 12 Na 24 11 e- -1 + Mg 12

22. What is its assigned atomic mass?
What isotope is used as the standard in the relative scale for atomic masses?
What is its assigned atomic mass?
Carbon-12
12 amu

23. Would Phosphorus-32 be stable?
15 protons, 17 neutrons
YES!

24. What experiment did Rutherford do and what 2 things did we learn from it about the atom?

25. Rutherford did the gold foil experiment
Bombarded a thin piece of gold foil with fast moving positively charged alpha particles
Expected the alpha particles to pass straight through. Most did, but 1 in were deflected back.
Learned that the atom is mostly empty space with a dense, positively charged core

26. What kind of nuclear reaction occurs in the sun and stars, making new elements?
Fusion!

27. 1. Identify the type of decay 2. How do you know?
Carbon-14 becomes nitrogen-14
Rn (radon) decays to become Po (polonium)
Lead (Pb) becomes Bismuth (Bi)
Polonium-214 becomes lead-210 β α β α

28. What does the mass number represent?
The number of protons + neutrons in the nucleus

29. Write the products of the following fusion reactions:4 2 He 4 2 Be 8 4 +
+ Energy C 12 6 He 4 2 O 16 8 +
+ Energy

30. Where is most of the mass of an atom?
In the nucleus

31. What is the name of the isotope that has 22 protons and 25 neutrons?
Titanium-47

32. Find how many half-lives have passed.
An organism contained 200 grams of Carbon-14 when it died. After 17,190 years, only 25 grams remain. How long is Carbon-14’s half-life?
Find how many half-lives have passed.
200 → 100 → 50 → 25
3 half-lives
17,190/3 = 5,730 years

33. Write the isotope symbol and hyphen notation for the name of the isotope that has 6 protons and 8 neutrons.
Carbon C 6

34. What is the law of conservation of mass?
Atoms are not subdivided, created or destroyed during a regular chemical reaction.

35. Name the 2 forces working in the nucleus of an atom.
Attractive Force: Strong Nuclear Force
Repulsive Force: Electrostatic Force

36. Write a radioactive decay equation that will produce/make Silver-108: - Using alpha decay - Using beta decay In
112 49 He 4 2 + Ag
108 47 Pd
108 46 e- -1 + Ag 47

37. How many protons, electrons, and neutrons are there in an atom of chlorine-37?
17p+; 17e-; 20n0

38. Draw a labeled diagram of the plum pudding model
Draw a labeled diagram of the plum pudding model. Who came up with this model?

40. Write the hyphen notation for the element that contains 15 electrons and 15 neutrons.
Phosphorous-30

41. How many protons, electrons, and neutrons are there in an atom of bromine-80?
35p+; 35e-; 45n0

42. How many neutrons does uranium-238 have?

43. 23Na Write the isotope symbol for the isotope of sodium with mass 2311

44. Which aspects of Dalton’s atomic theory were incorrect?
Atoms cannot be subdivided – we know atoms are made of protons, neutrons & electrons.
Atoms of a given element are identical in size, mass… - we know isotopes exist

45. How many protons does osmium-190 have?76

46. How do nuclides of the same element differ from each other (be specific)?
The have a different number of neutrons

47. State the 5 points of Dalton’s atomic theory
All matter is composed of atoms
Atoms of a given element are identical in size, mass, and other properties
Atoms cannot be subdivided, created, or destroyed
Atoms of different elements combine in simple whole-number ratios to form chemical compounds
In chemical reactions, atoms are combined, separated, or rearranged.

48. Mass decreases by 4 amu, Atomic number decreases by 2
When a nucleus undergoes alpha decay, what will happen to the mass? the atomic number?
When a nucleus undergoes beta decay, what happens to the mass? the atomic number?
Mass decreases by 4 amu, Atomic number decreases by 2
Mass doesn’t change, Atomic number increases by 1

49. What is the difference between fusion and fission
What is the difference between fusion and fission? Draw a picture showing the difference.
Fusion: combining 2 nuclei, more energy released than fission, stars and hydrogen bomb
Fission: splitting a nuclei, energy is released, nuclear powerplants and atomic bombs