Recitation 4 Last Name First Name 1 Identify each pure substance below as an element E or a compound C Potassium Chloride KCl Phosphorus P4 Chromium metal Cr Silver Bromide AgBr2 Oxygen gas O2 Sodium Sulfite Na2SO3 Barium Oxide BaO Nitrogen gas N2 2 Define each of the following laws Law Law of Conservation of Mass Description Law of Definite Proportions Law of Constant Composition Law of Multiple Proportions 3 Give an example of each of the following laws Law Law of Conservation of Mass Example Law of Definite Proportions Law of Constant Composition Law of Multiple Proportions 1 4 Provide the experiment and or the major discovery of each scientist listed below Experiment and or discovery Recitation 4 Scientist James Chadwick Robert Millikan Ernest Rutherford J J Thompson 5 Fill in the chart below 12 34 X 37 17 Number of protons Number of electrons Charge 2 0 6 Identify the element X below and fill in the chart for the number of protons neutrons and electrons found in each isotope 10 37 2 Element X Protons Neutrons Electrons Atomic number Mass number 7 A sample of Strontium created in the laboratory was designed to have a different isotopic distribution than naturally occurring strontium Using the data in the table below calculate the atomic mass of the lab sample of Strontium Recitation 4 Lab sample Isotope Exact Mass amu 84Sr 86Sr 87Sr 88Sr 83 913 85 909 86 909 87 906 Percent Abundance 32 00 8 00 18 00 42 00 The atomic mass of the Lab created sample of Sr is amu 8 The atomic mass of element Xy is 319 02 amu If Xy has two isotopes Xy 318 and Xy 321 what are the percent abundances of each of these isotopes Fill in the table below Isotope Exact Mass amu Percent Abundance 175Xy 176Xy 317 939 321 703 9 Classify each element as either a metal non metal or metalloid 3 Element Symbol Metal Element Symbol Nonmetal Metalloid Recitation 4 Metal Nonmetal Metalloid Zinc Germanium Iodine Chromium as a guide Mass in grams 10 Calculate and fill in the missing parts of the table below using the units in the column headers Mol atoms 18 6 g Magnesium 5 02 mol of Vanadium 39 1 g of F2 mol of F2 atoms of F 4 45 x 1024 atoms Ni Silicon Scandium Carbon Oxygen 4 11 What evidence exists that electromagnetic radiation light demonstrates wave like properties Recitation 4 12 What evidence shows that electromagnetic radiation light demonstrates particle like characteristics 13 What evidence shows that electrons demonstrate wave like properties 14 Define the following Wavelength Frequency Amplitude 5 15 Matching Fill in the blanks with the corresponding letter of the answer choice that best completes the statements Answer choices may be used more than once Answer Recitation 4 Choices Wavelength and frequency have a n relationship A Increases Frequency when wavelength decreases B Decreases Energy and frequency have a n relationship C Direct Energy when frequency increases D Inverse Energy and wavelength have a n relationship When wavelength decreases energy 16 Fill in the table below with the missing information Wavelength nm Frequency Hz or MHz Ephoton J 442 nm 940 nm 1 89 x 10 17 J 6 42 x 1012 Hz 104 1 MHz 6 17 Fill in the table below with the missing information Wavelength nm Frequency Hz photons released Ephoton J Etotal kJ Recitation 4 6 29 x 1014 2 moles 8 21 x 1024 photons 118 7 80 x 10 17 4 20 18 The lowest frequency photon for aluminum that demonstrates the photoelectric effect equals the binding energy of electrons resulting in their ejection is 9 87 1014 Hz What is the energy of one photon of this frequency 19 Answer the following statements about the photoelectric effect as True or False Shining a light of any wavelength or frequency long enough results in the ejection of electrons from a metal in experiments of the photoelectric effect A light of a certain wavelength when shone upon a metal surface resulted in the ejection of electrons Increasing the wavelength of the light will cause the electrons to be ejected with greater kinetic energy Shining a light of a particular wavelength did not result in the ejection of electrons from a metal Increasing the brightness of the light will cause electrons to be ejected A researcher noted that a particular wavelength of light did not result in the ejection of electrons from a metal To observe the photoelectric effect the researcher should increase the wavelength of the incoming light 7 20 According to Niels Bohr s model of the atom energy is and the electron of hydrogen in its ground state has n Recitation 4 21 Energy is any time an electron transitions from a higher n level to a lower n level and energy is any time an electron transitions from a lower n level to a higher one 22 Fill in the table below with the energies calculated in the transition and or the frequencies and the wavelengths of the energies in the following transitions of electrons in the Bohr model of the hydrogen atom Energy Absorbed or Emitted Ephoton J Hz nm ni 3 2 4 nf 6 3 Absorbed 434 2 1 60 x 1015 23 Why do line spectra suggest that energy is quantized 24 The Bohr model of the atom was dimensional and used just one quantum number n to describe an orbit of an electron within the atom The quantum mechanical model is dimensional and uses quantum numbers to describe an atomic orbital where the electron has a high probability of being located and quantum numbers to describe one electron at a time 8 Recitation 4 25 According to the principle the electrons fill orbitals from highest lowest energy to the highest lowest energy 26 Define the following Quantum Number Definition Description Range of Values 27 Fill in the table to indicate the possible inter values of n or m given the information in the table Then complete the table by filling in the number of electrons that may be described by that row s n and m n m Number of electrons described n m ms 1 2 2 3 3 4 0 2 0 3 1 1 0 2 3 9 28 Using the orbital diagram below draw half arrows electrons to represent Aluminum Recitation 4 29 Using the orbital diagram below draw half arrows electrons to represent Aluminum but this time show a violation of the Aufbau principle 30 Using the orbital diagram below draw half arrows electrons to represent the Aluminum ion Al3 10 31 Using the orbital diagram below draw half arrows electrons to represent Phosphorus Recitation 4 32 Using the orbital diagram below draw half arrows electrons to represent Phosphorus but this time show a violation of Hund s rule 33 Using the orbital diagram below draw half arrows