Name_________________________Per___________Date__________



Name_________________________Per___________Date__________

Atomic Structure Practice Review

Complete the following questions. Be sure to show all your work to receive credit.

1. Calculate the following for Bromine-80

|Protons |Electrons |Neutrons |

|35 |35 |45 |

2. Iridium has two isotopes 191Ir and 193Ir. Which isotope is more abundant? What is that percent abundance? Show all your work.

192.2 = (191 x X) + (193 x (1-X)

192.2 = 191X + 193 – 193X

-0.8 = -2X

Ir-191 = 40%

Ir-193 = 60 % - Most abundant

3. Silicon has three naturally occurring isotopes. Silicon- 28, Silicon-29, and Silicon-30. Using the information below calculate the average atomic mass of Silicon. (Show your work)

|Isotope |Exact Mass |% Abundance |

|Silicon- 28 |27.976927 |92.23 |

|Silicon-29 |28.976495 |? 4.67 |

|Silicon-30 |29.973770 |3.10 |

Avg atomic mass = (27.976927 x 0.9223) + (28.976495 x 0.0467) + (29.973770 x .0310)

Avg atomic mass = 28.0855 ( 28.1 amu

4. Give the nuclear symbol for the isotope Arsenic-76: 76As

33

Identify the following:

|Atomic Number |Mass Number |Protons |Neutrons |Electrons |

|33 |76 |33 |43 |33 |

5. What are isotopes?

• Atoms with the same number of protons and a different number of neutrons.

6. What are ions?

• An electrically charged atom due to the gain or loss of electrons.

7. How does an ion acquire a positive and negative charge?

• By gaining or losing electrons.

Identify each of the following elements using the format AX Z

|Description |Isotope |

|8. 77 protons and 75 electrons |192Ir |

| |77 |

|9. 25 electrons (neutral atom) |55Mn |

| |25 |

|10. mass number 208 and 126 neutrons |208Pb |

| |82 |

|11. 62 neutrons and 46 protons |108Pd |

| |46 |

12. Calculate the following for Mg+2.

|Protons |Electrons |Neutrons |

|12 |10 |12 |

13. Carbon has two naturally occurring isotopes Carbon -12 and Carbon-13.

The masses of the two isotopes are 12.00 amu and 13.003 amu respectively (in order). Calculate the relative abundance for the two isotopes of carbon.

12.01 = (12.00 x X) + (13.003 x (1-X)

12.01 = 12.00X + 13.003 – 13.003X

-0.993 = -1.003X

X = 0.99

C-12 = 99.00%

C-13 = 1.000%

14. Complete the table:

|Particle |Location |Mass |Charge |Discoverer |Experiment that led to |

| | | | | |discovery |

|n |Nucleus |1 |0 |Chadwick | |

|e- |Space surrounding |1/1837 |-1 |Thomson |Cathode Ray Tube |

| |nucleus | | | | |

15. What 3 ideas about the atom were determined by Rutherford’s gold foil

experiment?

a) Atoms formed a small dense center (mostly filled with empty space).

b) Nucleus was orbited by electrons.

c) Protons existed in nucleus.

16. What were the 5 principles of Dalton’s Atomic Theory?

a) All matter is composed of extremely small particles called atoms.

b) Atoms of an element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.

c) Atoms cannot be subdivided, created, or destroyed.

d) Atoms of different elements combine in simple whole-number ratios to form chemical compounds.

e) In chemical reactions, atoms are combined, separated, or rearranged.

Answer the following challenges.

17. A vacuum tube containing a filament and a fluorescent screen:

• Cathode Ray Tube

18. 9.1 x 10-31 kg:

• Mass of an electron

19. Has a relative mass of 1/1837:

• Electron

20. What discovery did the deflection of electrons in a cathode ray tube

lead to?

• All elements have electrons.

21. Has no charge and a mass of 1.6 x 10-27 kg:

• Neutron

22. Electrons embedded in a positively-charged sphere:

• Plum Pudding

23. Distinguishes a proton from a neutron:

• Charge

24. The two things involved in the oil drop experiment:

• Mass and Charge

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