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Chemistry Homework 4 Due date: Assignment: Complete the attached worksheets. 1 Part 1: Short Answer 1. The 3 particles of the atom are: a. __________________ b. __________________ c. __________________ 2. Their respective charges are: a. _________________ b. _________________ c. _________________ 3. The number of protons in one atom of an element determines the atom’s ________________ number. 4. The _____________ of an element is the total number of protons and neutrons in the ________________ of the atom. 5. What is the overall charge of the nucleus? 6. Give the symbol and the number of protons in one atom of: a. b. c. d. e. f. g. 7. Lithium _____________________________ Iron ________________________________ Oxygen _____________________________ Krypton _____________________________ Bromine ____________________________ Mercury ____________________________ Helium _____________________________ Give the symbol and the number of electrons in a neutral atom of: a. b. c. d. e. Uranium ____________________________ Boron ______________________________ Chlorine ____________________________ Iodine ______________________________ Xenon ______________________________ 2 8. Give the symbol and the number of neutrons in one atom of: a. b. c. d. e. f. g. Barium ____________________________ Carbon ____________________________ Fluorine ___________________________ Europium __________________________ Bismuth ___________________________ Hydrogen __________________________ Magnesium _________________________ 9. Name the element which has the following number of particles: a. b. c. d. e. f. 26 electrons, 29 neutrons, 26 protons _________________________ 53 protons, 74 neutrons ____________________________________ 2 electrons (neutral atom) __________________________________ 20 protons _______________________________________________ 82 electrons, 125 neutrons, 82 protons ________________________ 0 neutrons __________________________________ 10. If you know ONLY the following information, can you ALWAYS determine what the element is? (Yes/No) a. b. c. d. e. Atomic number _______________________________ Number of neutrons ___________________________ Number of protons ____________________________ Number of electrons in a neutral atom ____________ Mass number ________________________________ Part 2: Complete the table PROTONS NEUTRONS C 13 Be 10 20 Ne S 33 3 ELECTRONS Part 3: Matching _____ 1. proton a. the total number of protons and neutrons _____ 2. atom b. the weighted average mass of the atoms in a naturally occurring sample of an element _____ 3. mass number c. 1/12th of the mass of a carbon-12 atom _____ 4. atomic mass unit d. the number of protons in the nucleus of an atom _____ 5. electron e. atoms with the same number of protons but different number of neutrons _____ 6. isotopes f. negatively charged subatomic particle _____ 7. atomic number g. the smallest particle of an element that retains the properties of that element _____ 8. atomic mass h. the central part of an atom, containing protons and neutrons _____ 9. nucleus i. subatomic particle with no charge _____ 10. neutron j. positively charged subatomic particle Part IV: Multiple Choice 1. Which of the following is not a part of Dalton’s atomic theory? a. b. c. d. All elements are composed of atoms. Atoms of the same element are alike. Atoms are always in motion. Atoms combine in simple whole number ratios to form compounds. 2. The nucleus of an atom is: a. b. c. d. Negatively charged and has a low density Negatively charged and has a high density Positively charged and has a low density Positively charged and has a high density 4 3. Dalton theorized that atoms are indivisible and that all atoms of an element are identical. We now know that: a. b. c. d. Dalton’s theories are completely correct Atoms of an element can have different numbers of protons Atoms are divisible All atoms of an element are not identical but that must all have the same mass 4. The number of neutrons in the nucleus of an atom can be calculated by: a. b. c. d. Adding together the numbers of electrons and protons Subtracting the number of protons from the number of electrons Subtracting the number of protons from the mass number Adding the mass number to the number of protons 5. The sum of the protons and neutrons in an atom equals the: a. b. c. d. Atomic number Number of electrons Mass number Atomic mass 6. Which of these statements is false? a. b. c. d. Electrons have a negative charge Electrons have a mass of 1 amu The nucleus of an atom is positively charged The neutron is found in the nucleus of an atom 7. An atom of an element with the atomic number 48 and mass number 120 contains: a. b. c. d. 48 protons, 48 electrons, and 72 neutrons 72 protons, 48 electrons, and 48 neutrons 120 protons, 48 electrons, and 72 neutrons 72 protons, 72 electrons, and 48 neutrons 8. How do the isotopes hydrogen-2 and hydrogen-3 differ? a. b. c. d. Hydrogen-3 has one more electron than hydrogen-2. Hydrogen-3 has two neutrons and hydrogen-2 has only one. Hydrogen-3 has three protons and hydrogen-2 has two protons. Hydrogen-2 has no proton and hydrogen-3 has 1 proton. 5 9. The number 80 in the name bromine-80 represents: a. b. c. d. The atomic number The mass number The sum of the protons and electrons None of these 10. Which of these statements is not true? a. b. c. d. Atoms of the same element can have different mass numbers. The nucleus of an atom has a positive charge. Atoms of isotopes of an element can have different number of protons. Atoms are mostly empty space. 11. Relative atomic masses are measured in: a. b. c. d. nanograms grams anstrograms amu 12. The behavior of cathode rays produced in a glass tube containing a gas at low pressure led Thomson to conclude that the rays: a. b. c. d. Were not composed of matter Were composed of positively charged particles Were composed of negatively charged particles Were composed of uncharged particles 13. Who discovered the nucleus by bombarding gold foil with positively charged particles and noting that some particles were widely deflected? a. b. c. d. Rutherford Dalton Millikan Thomson 14. A nuclear particle that has about the same mass as a proton, but with no electrical charges is called a(n) a. b. c. d. Nuclide Neutron Electron Isotope 6 15. The mass of 1 mole of chromium (atomic mass 51.996 amu) is a. 12 g b. 198 g c. 51.996 g d. 6.02 * 1023 g Part V: Calculations: Be sure to round your answers to the correct number of significant figures. 1. There are five naturally occurring isotopes of the element zinc. The relative abundance and mass of each are as follows: Zinc-64 Zinc-66 Zinc-67 Zinc-68 Zinc-70 48.89% 27.81% 4.110% 18.57% 0.6200% 63.929 amu 65.926 amu 66.927 amu 67.925 amu 69.925 amu Calculate the average atomic mass of zinc. 2. Convert 4.50 moles of boron to grams of boron. 3. Convert 39.1 grams of silicon to moles of silicon 4. Convert 78.45 grams of lead to atoms or particles of lead 5. Convert 3.457 * 10-36 atoms of carbon to grams of carbon 7 Part VI: Electron Configurations – Write the electron configurations for the following elements: 1. He 2. N 3. S 4. Si 5. Al 6. Ca 7. Li 8. Be 9. Cl 10. Ne 11. Ar 12. Ca 13. K 14. O 15. F 16. H 17. Mg 18. Na 19. C 20. B 8