August 2007 Chemistry Regents #1-10
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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50 |
Questions | Answer | Explanations |
| 1 What was concluded about the structure of the atom as the result of the gold foil experiment? (1) A positively charged nucleus is surrounded by positively charged particles. (2) A positively charged nucleus is surrounded by mostly empty space. (3) A negatively charged nucleus is surrounded by positively charged particles. (4) A negatively charged nucleus is surrounded by mostly empty space. | 2 | open space positive nucleus |
| 2 An atom is electrically neutral because the (1) number of protons equals the number of electrons (2) number of protons equals the number of neutrons (3) ratio of the number of neutrons to the number of electrons is 1:1 (4) ratio of the number of neutrons to the number of protons is 2:1 | 1 | see answer |
| 3 How do the energy and the most probable location of an electron in the third shell of an atom compare to the energy and the most probable location of an electron in the first shell of the same atom? (1) In the third shell, an electron has more energy and is closer to the nucleus. (2) In the third shell, an electron has more energy and is farther from the nucleus. (3) In the third shell, an electron has less energy and is closer to the nucleus. (4) In the third shell, an electron has less energy and is farther from the nucleus. | 2 | 3rd energy level has more energy than the first It is also further from the nucleus |
| 4 Which element is a solid at STP and a good conductor of electricity? (1) iodine (3) nickel (2) mercury (4) sulfur | 3 | the metal, not liquid mercury |
| 5 Which element has both metallic and nonmetallic properties? (1) Rb (3) Si (2) Rn (4) Sr | 3 | metalloid (on the staircase on the PT) |
| 6 The carbon atoms in graphite and the carbon atoms in diamond have different (1) atomic numbers (2) atomic masses (3) electronegativities (4) structural arrangements | 4 | properties due to different structures |
| 7 Atoms of which element have the greatest tendency to gain electrons? (1) bromine (3) fluorine (2) chlorine (4) iodine | 3 | definition of electronegativity Table |
| 8 Which statement describes a chemical property of the element magnesium? (1) Magnesium is malleable. (2) Magnesium conducts electricity. (3) Magnesium reacts with an acid. (4) Magnesium has a high boiling point. | 3 | look for the reaction |
| 9 Matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as (1) a compound (3) a mixture (2) an isotope (4) a solution | 1 | definition of a compound |
| 10 Given the balanced equation representing a reaction: 2CO(g) + O2(g)<==> 2CO2(g) What is the mole ratio of CO(g) to CO2(g) in this reaction? (1) 1:1 (3) 2:1 (2) 1:2 (4) 3:2 | 1 | look at the #s in front for the mol ratio 2:2 which reduces to 1:1 |