1- Radioactivity is a tendency for an element or a material to ________.
2- Which of the following provides the minimum amount of protection you need to block the following form of radiation?
Alpha
| Suntan lotion (or human skin) |
Flag this Question 3- Which of the following types of radiation might be best for medical imaging?
| Alpha radiation would be best because it penetrates the least and therefore does the least damage. |
| Gamma radiation would be best because it penetrates the best. |
| Beta radiation would be best because it can be measured electrically. |
| Only X-rays are used for medical imaging. |
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4- Which of the following statements best describes the role of neutrons in the nucleus?
| The neutrons stabilize the nucleus by forming bonds with other neutrons. |
| The neutrons stabilize the nucleus by acting as "nuclear cement". |
| The neutrons stabilize the nucleus by attracting electrons. |
| The neutrons stabilize the nucleus by balancing charge. |
Flag this Question 5- If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount?
Flag this Question 6- Why is the carbon-14 dating not accurate for estimating the age of materials more than 50,000 years old?
| This form of radioactive dating is only accurate back 1,400 years |
| The concentration of carbon-14 in a body after 50,000 years is too low. |
| Living organisms are too decomposed after 50,000 years. |
| Actually, carbon-14 dating is accurate back to around 5 million years ago. |
7- Why will nuclear fission probably not be used directly for powering automobiles?
| Massive shielding would be required to protect against radioactivity exposure. |
| Radioactive wastes could not be adequately controlled. |
| It's more practical for cars to use the electricity generated by nuclear fission power plants. |
| All of the above are true. |
8- What does Einstein's energy equation (E = mc2) say about the energy that is derived from nuclear fission reactions?
| The energy is proportional to the change in mass of the electrons of the atom that is undergoing fission. |
| The energy released is due to the missing mass of the products compared to the mass of the starting materials. |
| The energy is derived from the light that is emitted when the atom splits. |
| The energy equation does not apply towards fission, only fusion. |
Flag this Question 9- Where does the earth receive most of its energy?
Flag this Question 10- What are some of the optimistic worldwide changes that may follow the advent of successful fusion reactors?
| Economies will be geared to relative abundance rather than scarcity. |
| Humans will have more opportunities to focus on social issues, such as world hunger. |
| There will be fewer hostilities between nations |
11- What is the valence shell?
| It is the shell of electrons in an atom that is the least reactive |
| It is the outermost shell of electrons in an atom |
| It is the last partially filled orbital in an atom. |
| It is the shell of electrons in element V (atomic no. = 23) |
12- Which of the following is NOT an ion?
13- What needs to be done to convert a neutral nitrogen atom N into an N3- species
Flag this Question 14- Which of the following elements will most likely not form an ion at all?
Flag this Question 15- Calcium fluoride, Mg3N2, is an example of ________.
| a polar covalent compound |
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16- How many chloride ions (Cl1-) are needed to balance the positive charge of a barium ion (Ba 2+)?
Flag this Question 17- The number of nonbonding pairs in the water molecule is
18- Which of the following molecules has a molecular shape that is linear?
Flag this Question 19- Which of the following molecules contains a polar covalent bond?
Flag this Question 20- Which of the following bonds would be the most polar?