chemistry hard core, it’s just hard….
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| 2. The common isotopes of carbon are 12C and 13C. The average mass of carbon is 12.01115 amu. What is the abundance of the 13C isotope? | |
| (a) | 1.115% |
| (b) | 98.885% |
| (c) | 0.480% |
| (d) | 99.52% |
| 3. If the abundance of 6Li (6.015121 amu) is 7.500% and the abundance of 7Li (7.016003 amu) is 92.500%, what is the average atomic mass? | |
| (a) | 6.0750 amu |
| (b) | 6.0902 amu |
| (c) | 6.9250 amu |
| (d) | 6.9409 amu |
4. What do the following have in common?
|
|
| (a) | They are isotopes of each other. |
| (b) | They are isomers of each other. |
| (c) | They are isoelectronic with each other. |
| (d) | They are different elements so they have nothing in common. |
| 5. How many valence electrons does an oxygen atom have? | |
| (a) | 2 |
| (b) | 6 |
| (c) | 8 |
| (d) | 16 |
| 6. Fluorine atoms tend to…?…when they form chemical compounds with metals. | |
| (a) | lose electrons |
| (b) | gain electrons |
| (c) | neither lose nor gain electrons…they usually share electrons equally with metals. |
| (d) | Fluorine atoms do not form compounds with other atoms…fluorine is an inert gas. |
| 7. The identity of an element is determined by… | |
| (a) | the number of its protons. |
| (b) | the number of its neutrons. |
| (c) | the number of its electrons. |
| (d) | its atomic mass. |
| 9. Which of the following electron configurations represents the electron configuration for a magnesium cation…Mg2+? | |
| (a) | 1s22s22p63s2 |
| (b) | 1s22s22p63s23p2 |
| (c) | 1s22s22p6 |
| (d) | 1s22s22p4 |
| 11. The half-life of francium-212 is 19 minutes. How many minutes will it take for 1 gram of this isotope to decay to 0.125 grams? | |
| (a) | 4.75 minutes |
| (b) | 9.5 minutes |
| (c) | 38 minutes |
| (d) | 57 minutes |
| 12. The atom formed by the beta decay of carbon-14 is… | |
| (a) | oxygen-18 |
| (b) | beryllium-10 |
| (c) | boron-14 |
| (d) | nitrogen-14 |
