Version001–APHomework2–sanftner–(s30501) 1 This print-out should have 26 questions. Multiple-choice questions may continue on 3. Matter is composed of atoms. the next column or page – find all choices before answering. 4. Atoms of the same element have the same properties. Mlib 02 1071 001 10.0 points CIC T02 29 The atomic weight of lithium is 6.941 amu. 004 10.0 points There are two naturally occurring isotopes of The atomic number is the 6 lithium. Li has an isotopic mass of 6.0151 7 amu and Li has an isotopic mass of 7.0160 1. number of protons in a nucleus. 7 amu. What is the percent abundance of Li? 2. same as the mass number of an atom. 1. 89.2 percent 3. number of neutrons in a nucleus. 2. 4.3 percent 4. number of protons and neutrons in the 3. 95.7 percent nucleus.

4. 92.5 percent Brodbelt 520053 005 10.0 points 5. 7.8 percent A new element has two isotopes, one with a mass of 40.0 amu and the other with a mass of Mlib 02 0031 42.0 amu. The atomic weight is 40.50 g/mol. 002 10.0 points Pick the true statement. Identify the incorrect statement regarding Dalton’s Atomic Theory. 1. The element has 20 protons and 21 elec- trons. 1. All matter is composed of protons, elec- trons, and neutrons. 2. The isotope at 42.0 amu is more abun- dant. 2. All atoms of a given element are identi- cal. 3. Both isotopes are equally abundant.

3. All matter is composed of atoms. 4. The element is calcium.

4. A given compound always has the same 5. There is not enough information given. relative numbers and types of atoms. 6. The element has 19 protons and 21 neu- Mlib 76 0007 trons 003 10.0 points Which one of the following is NOT part of 7. The isotope at 40.0 amu is more abun- Dalton’s atomic theory? dant.

1. Atoms of different elements have different Mlib 02 0017 properties. 006 10.0 points Cathode rays all have the same negative 2. Atoms change into other atoms in chemi- charge. cal reactions. Version001–APHomework2–sanftner–(s30501) 2 1. True 010 10.0 points Whose research showed that atoms consist of 2. False small positively charged nuclear centers and lots of empty space populated by electrons? Mlib 02 0049 007 10.0 points 1. Rydberg Rutherford’s gold foil experiment demon- strated that 2. Thomson

1. electrons must have quantized energy lev- 3. Einstein els. 4. Rutherford 2. Dalton was correct in claiming that atoms are hard, structureless spheres. 5. Bohr

3. lead could be transformed into gold. DAL 05 05 011 10.0 points 4. the positive charge in an atom must reside Which scientist discovered that the atomic in a dense core much smaller than the atom. number, rather than the atomic weight, is more responsible for the properties of an el- Mlib 02 0083 ement? (Tragically this scientist died soon 008 10.0 points after as a soldier in WWI.) Thomson’s experiment measured 1. Rutherford 1. the mass of a proton. 2. Moseley 2. the mass of an electron. 3. Chadwick 3. the size of the nucleus of an atom. 4. St. Augustine 4. the charge of the electron. 5. Millikin 5. the charge to mass ratio of an electron. Holt da 3 rev 19 Mlib 76 0069 012 10.0 points 009 10.0 points Three isotopes of argon occur in nature – 36 38 40 Millikan’s oil drop apparatus allowed for the 18Ar, 18Ar, 18Ar. Calculate the average determination of which property of the elec- atomic mass of argon to two decimal places, tron? given the following relative atomic masses and the abundances of each of the isotopes: argon- 1. ratio of mass to charge 36 (35.97 amu; 0.337%), argon-38 (37.96 amu; 0.063%), argon-40 (39.96 amu; 99.600%). 2. speed 1. 37.95 amu 3. charge 2. 39.95 amu 4. mass 3. None of these Msci 02 1141 Version001–APHomework2–sanftner–(s30501) 3 4. 35.96 amu 2. 27.3%

5. 37.96 amu 3. 45.8%

6. 119.89 amu 4. 54.2%

7. 39.96 amu 5. 37.5%

8. 35.97 amu 6. 72.7%

Mlib 02 1003 Mlib 02 0061 013 10.0 points 016 10.0 points 14 0 6C → −1e + ? The following are all proposals of Dalton’s The missing isotope is atomic theory. Which part of Dalton’s atomic theory was shown to be wrong by the discov- 14 1. 7N ery of natural radioactivity?

15 1. Atoms are permanent, unchanging, indi- 2. 6C visible bodies. 13 3. 6C 2. Atoms of a given element all weigh the same. 14 4. 5B 3. Atoms combine in simple numerical ratios Mlib 02 1053 to form compounds. 014 10.0 points 4. Two or more kinds of atoms may combine Isotopes have the same number of (neutrons, in different ways to form more than one kind protons) with different numbers of (electrons, of chemical compound. neutrons, protons). 5. Compounds consist of collections of 1. protons; neutrons molecules made up of atoms bonded to- gether. 2. neutrons; electrons

3. neutrons; protons Mlib 02 0019 017 10.0 points 4. protons; electrons Cathode rays are (electrons, neutrons, pro- tons) and have the (largest, smallest) Brodbelt 05 06 charge/mass ratio of the fundamental par- 015 10.0 points ticles found in the atom. The atomic weight of a newly discovered el- 1. ement is 110.352 amu. It has two naturally neutrons; largest occuring isotopes. One has a mass of 111.624 2. protons; smallest amu. The other has an isotopic mass of 109.875 amu. What is the percent abundance 3. electrons; largest of the last isotope (109.875 amu)? 4. None of the other answers is correct. 1. 62.5% Version001–APHomework2–sanftner–(s30501) 4 5. protons; largest fields.

Mlib 02 0043 2. All of these provided evidence of the fun- 018 10.0 points damental nature of cathode rays. Most of the volume occupied by a piece of copper is taken up by the volume of the copper 3. The rays were deflected by magnetic nuclei. fields.

1. False 4. The rays were independent of the type of gas in the vacuum tube. 2. True Holt da 3 3 rev 3a Mlib 02 0092 022 10.0 points 019 10.0 points Choose the correct nuclear symbol and hy- Which scientist is associated with the discov- phen notation for the isotope which has a ery of the electron? mass number of 28 and atomic number of 14.

28 1. Millikan 1. 14Si, silicon-28

14 2. Rutherford 2. 14P, phosphorus-14

3. Dalton 14 3. 14S, sulfur-14 4. Bohr 28 4. 14S, sulfur-28 5. Thomson 14 5. 28S, sulfur-14 Mlib 76 0097 020 10.0 points 14 6. 28Si, silicon-14 When combined with Thomson’s determina- tion of the charge to mass ratio of the electron, 28 Millikan’s experimental work allowed for the 7. 14P, phosphorus-28 determination of the 14 8. 28P, phosphorus-14 1. speed of the electron. 14 9. 14Si, silicon-14 2. charge on the electron.

3. All of these Holt da 3 3 rev 3c 023 10.0 points 4. mass of the electron. Choose the correct nuclear symbol and hy- phen notation for the isotope which has 56 Mlib 76 2102 protons and 82 neutrons. 021 10.0 points 82 Which experimental observation led scientists 1. 56Ba, barium-56 to speculate that cathode rays contained par- 56 ticles that were constituents of all matter? 2. 82Ba, barium-82

1. 82 The rays were deflected by electrical 3. 56I, iodine-82 Version001–APHomework2–sanftner–(s30501) 5

138 4. 82I, iodine-82 Mlib 02 1049 026 10.0 points 138 5. 56Ba, barium-138 How many protons are present in the stable form of the sulfide ion? 138 6. Xe, xenon-56 56 1. 15 56 7. 138Xe, xenon-82 2. 16

82 8. 138Xe, xenon-138 3. 14

138 9. 56I, iodine-56 4. 17

5. 18 Msci 05 0409 024 10.0 points The experimental evidence for the develop- ment of the nuclear model of the atom was

1. Thomson’s cathode ray tubes.

2. canal rays.

3. Rutherford’s gold foil experiment.

4. the Heisenberg experiment.

5. line spectra.

6. Millikan’s oil drop experiment.

Msci 05 0103 025 10.0 points A magnesium (Mg) atom with a mass number of 25 contains

1. 13 protons, 12 neutrons and 12 elec- trons.

2. 25 protons, 25 neutrons and 25 elec- trons.

3. 12 protons, 13 neutrons and 12 elec- trons.

4. 25 protons, 13 neutrons and 25 elec- trons.

5. None of these