A. Element 1. The number of protons and neutrons of an atom.

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1 Unit 03: Test Review Atoms and Elements Key Term Definition A. Element 1. The number of protons and neutrons of an atom. B. Atom 2. The smallest particle of an element. C. Atomic Number 3. A primary substance that cannot be broken down into simple substances. D. Mass Number 4. An atom of an element that has a different number of neutrons than another atom of the same element. E. Isotope 5. The number of protons in an atom. Chemical Symbols Write the symbol for each of the following elements: 1. carbon 6. iron 11. sodium 2. phosphorus 7. oxygen 12. nitrogen 3. iodine 8. sulfur 13. potassium 4. lead 9. calcium 14. gold 5. copper 10. neon 15. chlorine Write the names of the elements represented by each of the following symbols: 1. Mg 7. K 2. Au 8. F 3. Cu 9. Be 4. Ag 10. Br 5. Zn 11. Al 6. Ba 12. Li The Periodic Table Indicate whether the following are in the same group (G), period (P) or neither (N) 1. Li, C and O 5. Br, Cl and F 2. Al, Si and Cli 6. C. N and O 3. Mg, Ca and Ba 7. C, S, and Br 4. Li, Na and K 8. K, Ca and Br

2 Complete the list of elements, group numbers and period numbers for the following table: Element/Symbol Group Number Period Number 2A 3 Silicon/Si 5A 2 Aluminum/Al 4A 5 1A 6 Identify each of the following as a metal (M) or nonmetal (NM) 1. C 3. N 5. Fe 7. K 9. Al 2. C 4. Ca 6. Zn 8. Ag 10. Mg Place the following atoms into the correct group of elements: K, Cl, He, Fe, Mg, Ne, Li, Cu and Br 1. Halogens 2. Noble Gases 3. Alkali Metals 4. Alkaline Earth Metals 5. Transition Metals The Atom True/False 1. All matter is composed of atoms. 2. All atoms of an element are identical. 3. Atoms combine to form compounds. 4. Most of the mass of the atom in the nucleus.

3 Key Term Definition A. Proton 1. Found in the nucleus of an atom B. Neutron 2. Found outside the nucleus C. Electron 3. The small, dense center of an atom D. Nucleus 4. Has a (-1) charge 5. Has a mass of 1 amu 6. Is neutral Atomic Number and Mass Number Give the number of protons in each of the following neutral atoms: 1. An atom of Carbon 2. An atom of the element with the atomic number An atom with a mass number of 40 and an atomic number An atom with 9 neutrons and a mass number of A neutral atom that has 18 electrons Find the number of neutrons in each of the following atoms: 1. A mass number of 42 and atomic number A mass number of 10 and 5 protons Si A mass number of 9 and atomic number 4 5. A mass number of 22 and 10 protons 6. A zinc atom with a mass number of 66

4 Symbol Atomic Number Mass Number Protons Neutrons Electrons Sn Identify the sets of atoms that are isotopes: X X X X X

5 Average Atomic Miss Calculations 1. Rubidium is a soft, silvery-white metal that has two common isotopes, 85 Rb and 87 Rb. If the abundance of 85 Rb is 72.2% and the abundance of 87 Rb is 27.8%, what is the average atomic mass of rubidium? 2. Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three common isotopes. If the abundance of 234 U is 0.01%, the abundance of 235 U is 0.71%, and the abundance of 238 U is 99.28%, what is the average atomic mass of uranium? 3. Titanium has five common isotopes: 46 Ti (8.0%), 47 Ti (7.8%), 48 Ti (73.4%), 49 Ti (5.5%), 50 Ti (5.3%). What is the average atomic mass of titanium? 4. Calculate the average atomic mass of sulfur if 95.00% of all sulfur atoms have a mass of amu, 0.76% has a mass of amu and 4.22% have a mass of amu. 5. Calculate the average atomic mass of bromine. One isotope of bromine has an atomic mass of 78.92amu and a relative abundance of 50.69%. The other major isotope of bromine has an atomic mass of 80.92amu and a relative abundance of 49.31%. 6. Naturally occurring chlorine that is put in pools is percent 35 Cl (mass = amu) and percent 37 Cl (mass = amu). Calculate the average atomic mass. Conceptual Question: Copper has two naturally occurring isotopes: 63 Cu and 65 Cu. If that is the case, why is that average atomic mass of copper listed as on the periodic table?

6 Nuclear Radiation 1. What is nuclear radiation? 2. In nuclear medicine, iodine-125 is used for detecting a tumor in the thyroid. What does the number 125 used in the name indicate? 3. How does nuclear fission differ from nuclear fusion? Key Term A. radioactive nucleus Definition 1. A particle identical to a helium nucleus produced in a radioactive nucleus. B. Half-life 2. The time required for one-half of a radioactive sample of undergo radioactive change C. curie 3. A unit of radiation that measures the activity of a sample D. nuclear fission 4. A process in which large nuclei split into smaller nuclei with the release of energy E. alpha particle 5. A nucleus that spontaneously emits radiation Radioactivity Key Term Definition A. 18 8O 1. Symbol for a beta particle B. ɣ 2. Symbol for an alpha particle C. Radioactive isotope 3. An atom that emits radiation D. 4 2He 4. Symbol for an atom of oxygen E. β 5. Symbol for gamma radiation (1) Describe methods that you can use to limit the amount of radiation you would receive if you regularly work with radioactive substances in your profession.

7 (2) Which type(s) of radiation (alpha, beta, gamma) would each of the following shielding materials protect you from? (a) clothing (d) skin (b) paper (e) concrete (c) lead wall Nuclear Equations (1) 66 29Cu 66 30Zn + (2) U 4 2He + (3) 24 11Na 0-1e + (4) 30 14Si + 0-1e (5) 40 20Ca K + 1 1H (6) 27 13Al + 1 0n 24 11Na + (7) 10 B + 1 n He + (8) Na Mg n (9) Au H n

8 Half-Lives (1) Supposed you have an 80-mg sample of iodine-125. If iodine-125 has a half-life of 60 days, how many mg are radioactive (a) After one half-life? (b) After two half-lives? (c) After 240 days? (2) 99 Tc has a half-life of 6 hours. If a technician picked up a 16 mg sample at 8AM, how much of the radioactive sample remained at 8PM on the same day? (3) Phosphorus-32 as a half-life of 14 days. How much of the 240-mg sample will be radioactive after 56 days? (4) Iodine-131 has a half-life of 8 days. How many days will it take for 80-mg of I-131 to decay to 5-mg? (5) Suppose a group of archaeologists digs up some pieces of a wooden boat at an ancient site. When a sample of the wood is analyzed for C-14, scientists determine that 12.5% (or ⅛) of the original amount of C-14 remains. If the half-life of carbon-14 is 5730 years, how long ago was the boat made? (6) Use this graph to answer the following questions: (7) (a) What is the half life of this substance? (b) How much remains after 3 half-lives?

9 Practice Test Questions on Nuclear Chemistry (1) The correctly written symbol for at atom of sulfur is (a) 30 S 16 (b) 14 S 30 (c) 30 S 16 (d) 30 S 16 (e) 16 S 30 (2) Alpha particles are composed of (a) Protons (c) neutrons (e) electrons (b) protons and electrons (d) protons and neutrons (3) Gamma radiation is the type of radiation that (a) Originates in the electron shells (b) Is most dangerous (c) Is least dangerous (d) Is the heaviest (e) Goes the shortest distance (4) The charge on an alpha particle is (a) (-1) (b) (+1) (c) (-2) (d) (+2) (e) (+4) For questions 5-9, select from the following: (a) 0 X -1 (b) 4 He 2 (c) 1 X 1 (d) 1 X 0 (e) 0 X 0 (5) An alpha particle (6) A Beta particle (7) A Gamma Ray (8) A proton (9) A neutron (10) Shielding from gamma rays is provided by (a) skin (b) paper (c) clothing (d) lead (e) air (11) The radioisotope iodine-131 is used as a radioactive tracer for studying thyroid gland activity. The symbol for iodine-131 is (a) I (b) 131 I (c) 131 I 52 (d) 53 I 131 (e) 78 I 53 (12) When an atom emits an alpha particle, its atomic mass will (a) Increase by 1 (b) increase by 2 (c) increase by 4 (d) decrease by 4 (e) will not change (13) When a nucleus emits a beta particle, the atomic number of the new nucleus (a) Increases by 1 (b) increases by 2 (c) decreases by 1 (d) decreases by 2 (e) will not change (14) What a nucleus emits a gamma ray, the atomic number of the new nucleus (b) Increases by 1 (b) increases by 2 (c) decreases by 1 (d) decreases by 2 (e) will not change

10 For questions 15-18, select the particle that best completes each equation (a) neutron (b) alpha particle (c) beta particle (d) gamma ray (15) 126 Sn Sb + (16) 69 Zn Ga + (17) 99 Tc Tc + (18) 149 Sm Nd + (19) What symbol completes the following reaction? 14 7 N n H (a) 15 8 O (b) 15 6 C(c) 14 8 O (d) 14 6 C(e) 15 7 N (20) To complete this nuclear equation, you need to write: Fe Ni n (a) alpha particle (b) beta particle (c) gamma (d) neutron (e) proton (21) The time required for a radioisotope to decay is measured by its (a) Half-life (b) protons (c) activity (d) fusion (e) radioisotope (22) Oxygen-15 used in PET imaging has a half-life of 2 min. How many half-lives have occurred in the 10 minutes it takes to prepare the sample? (a) 2 (b) 3 (c) 4 (d) 5 (e) 6 (23) Iodine-131 has a half-life of 8 days. How long will it take for a 160-mg sample to decay to 10-mg? (a) 8 days (b) 16 days (c) 32 days (d) 40 days (e) 48 days (24) Phosphorus-32 has a half-life of 14 days..after 28 days, how many mg of a 100-mg sample will still be radioactive? (a) 75 mg (b) 50 mg (c) 40 mg (d) 25 mg (e) 12.5 mg (25) The splitting of a large nucleus to form smaller particles accompanied by a release of energy is called (a) Radioisotope (b) fission (c) fusion (d) rem (e) half-life (26) The process of combining small nuclei to form larger nuclei is (a) Radioisotope (b) fission (c) fusion (d) rem (e) half-life