CHEM 1010 – Chapter 4 – Flashcards
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Which of the following best explains what is happening when an atom emits light?
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An electron is dropping from a higher to a lower energy level with the difference in energy between the two being emitted as light energy.
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How are frequency and wavelength related?
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The higher the frequency the lower the wavelength.
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Which of the following determined the ratio of the charge of an electron to its mass?
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J.J. Thompson's cathode ray deflection experiments
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The following statement describes which subatomic particle best? It has a relatively large mass.
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(E) B and C
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An element found in another galaxy exists as two isotopes. If 80.0 percent of the atoms have an atomic mass of 80.00 amu and the other 20.0 percent have an atomic mass of 82.00 amu, what is the atomic mass of the element?
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80.4 amu
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From which of the following atoms would removing an electron be the easiest? (Rb, Sr, Cd, I)
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Rb
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The following statement describes which subatomic particle best? It is located outside of the nucleus.
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(A) an electron
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In some instances electromagnetic radiation behaves like a wave. In other instances electromagnetic radiation behaves more like a particle. Which behavior more accurately describes the true nature of electromagnetic radiation?
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Electromagnetic radiation behaves both as a wave or as a particle depending on the circumstance.
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Oxygen, O, (number 8), sulfur, S, (number 16), and selenium, Se, (number 34) have such similar chemical properties because
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their outermost shells contain the same number of electrons
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How might you distinguish a sodium-vapor street lamp from a mercury-vapor street lamp?
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look at the street lamps through a spectroscope and match their spectral patterns to their respective atomic spectra
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Which of the following is said to be quantized?
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the number of eggs in an egg carton
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Isotopes of the same element have a different number of
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neutrons
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From which of the following atoms would removing an electron be the most difficult? (Rb, Sr, Cd, Xe)
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Xe
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A beam of protons and a beam of neutrons of the same energy are both harmful to living tissue. The beam of neutrons, however, is less harmful. Why?
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Neutrons carry no electric charge and thus have a greater likelihood of passing through the tissue.
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If two protons and two neutrons are removed from the nucleus of the oxygen-16 isotope, a nucleus of which element remains?
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carbon-12
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How is it possible to deduce the identity of an element from its electron configuration?
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An electron configuration is unique to each element, much like its atomic spectrum.
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Each atomic orbital can hold
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up to 2 electrons
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The following statement describes which subatomic particle best? It is a nucleon.
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(D) B and C
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How is the term photon related to the term quantum?
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A quantum of light is actually one photon.
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What does the following element description actually mean? hydrogen-2
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a hydrogen with one neutron and one proton
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Which of the following statements does not describe a proton?
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It orbits around the nucleus of an atom.
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Rutherford assumed that the atomic nucleus was positively charged because
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the alpha particles that ricocheted off of the nucleus are also positively charged
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Which of the following atoms is the largest? (Cs, Ba, Al, N, He)
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Cs
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The nucleus of an electrically neutral iron atom contains 26 protons. How many electrons does this iron atom have?
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26
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Which of the following is not a property of an electron?
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charge changes depending on mass
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Which element has the atomic number 12?
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Mg
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An element has two different isotopes: one that weighs 65 amu and another that weighs 67 amu. If the average atomic mass of all the isotopes is 66.5 amu, what can be said about the relative abundance of the isotopes?
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The isotope with the mass of 67 is more abundant than the isotope with the mass of 65.
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Which of the following statements is false?
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An atom emits electromagnetic radiation when an electron moves from a lower energy level to a higher energy level.
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Which of the following is not a form of electromagnetic radiation?
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sound waves
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Rank the following by the relative amounts of energy, from most energetic to least:
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gamma rays, blue light, red light, radio waves
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It is relatively easy to pull an electron away from a potassium atom (K, atomic number 19), but very difficult to remove a second one because
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of a much greater effective nuclear charge
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If a neutral element has the following chemical notation, how many electrons does it have? carbon-13
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6
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Which of the following might best explain the reason why electrons are restricted to certain energy levels in an atom?
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They behave like restricted waves and are self-reinforcing.
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Which of the following atoms is the smallest?
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F
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If an element has 10 protons and 11 neutrons and 10 electrons, which expression correctly identifies the element?
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neon-21
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Which of the following gases would diffuse the fastest through an extremely fine membrane?
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He
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If an element has 18 protons and 20 neutrons and 18 electrons, which expression correctly identifies the element?
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argon-38
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Which of the following statements is true about Bohr's planetary model of the atom?
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The electrons orbit around the nucleus.
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Since atoms are mostly empty space, why don't objects pass through one another?
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The electrons on the atoms repel other electrons on other atoms when they get close.
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How does Rutherford's model of the atom explain why some of the alpha particles directed at the gold foil were deflected straight back toward the source?
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The atomic nucleus is very small but dense and carries a positive electric charge.
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Which of the following statements best describes electromagnetic radiation?
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Light waves are oscillations of electric and magnetic fields.
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How does the wave model of electrons orbiting the nucleus account for the fact that the electrons can have only discrete energy values?
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When an electron wave is confined, it is reinforced only at particular frequencies.
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The shell model presented in this book is not very accurate. Why then is it presented?
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The shell model is simpler, useful and easy to understand.
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The energy level diagram ranks orbitals by their
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average distance from the nucleus
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List the following elements in order of increasing ionization energy: Tin, Sn; Lead, Pb; Phosphorus, P; Arsenic, As.
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Sn < Pb < As < P
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What is the approximate mass of a carbon atom in atomic mass units (amu)? How about a carbon dioxide molecule?
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A carbon atom has a mass of about 12 amu. Carbon dioxide would then have a mass of 44 amu.
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If you remove two protons and two electrons from a sulfur atom (S), what new element is formed?
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Si
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Which of the following experiments helped to determine that most of an atom is actually empty space except for a very small positive core?
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E. Rutherford's gold foil experiments
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The mass number of an element is
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the sum of the protons and the neutrons
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In Rutherford's gold foil experiment, alpha particles
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were deflected by the atomic nucleus
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If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element?
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atomic mass, 99 amu; Technetium
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Which of the following experiments helped to determine the charge of an electron and (indirectly) its mass?
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R. Millikan's oil drop experiments
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Which of the following could best be represented by a physical model?
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(A) a cell
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If an element has 15 protons and 16 neutrons and 15 electrons, what is the atomic mass of the element?
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31
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The following statement describes which subatomic particle best? It is electrically charged.
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(D) A and B
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An electron in the outermost shell of which group 1 element experiences the greatest effective nuclear charge (if any)?
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all have the same
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How might the spectrum of an atom appear if its electrons were not restricted to particular energy levels?
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A broad spectrum of all colors would be observed.
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Which of the following concepts underlies all the others: ionization energy, effective nuclear charge, atomic size.
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effective nuclear charge
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Which of the following statements describes an isotope?
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element with the same number of protons but a different number of neutrons
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What do the electron configurations for all the group 18 noble gases have in common?
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Their outermost occupied shells are filled to capacity.
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What does the following element description actually mean? 92U-238
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a uranium atom with 92 protons and 146 neutrons
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Boron has primarily two isotopes, one with an atomic mass of 11.0 amu and another with an atomic mass of 10.0 amu. If the abundance of the boron atom with a mass of 11.0 amu is 18.9 percent and the abundance of the other isotope is 81.1 percent, what would be the average mass of the boron atom?
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10.2 amu
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Another interesting periodic trend is the density of the elements. We find that osmium, Os (atomic number 76) has the greatest density of all elements, and, with some exceptions, the closer an element is positioned to osmium, the greater its density. Based upon this trend, list the following elements in order of increasing density: copper, Cu, gold, Au, platinum, Pt, and silver, Ag.
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copper, Cu < silver, Ag < gold, Au < platinum, Pt
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How many electrons are there in the third shell of sodium, Na (atomic number 11)?
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one
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Which of the following is a property of light?
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all of the above
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The ________ represents the complete range of frequencies of light energy from radio waves to gamma rays.
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electromagnetic spectrum
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How is it possible for an atom to emit visible light even though the atom is smaller than the wavelength of visible light?
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Any charged object, including the smallest atom, generates electromagnetic waves as it vibrates, which we observe in the visible spectrum of an element.
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If a neutral element has the following chemical notation, how many electrons does it have? fluorine-19
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9
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How can a hydrogen atom, which has only one electron, have so many spectral lines?
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Because there is more than one energy level in a hydrogen atom.
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The isotope lithium-7 has a mass of 7.0160 atomic mass units, and the isotope lithium-6 has a mass of 6.0151 atomic mass units. Given the information that 92.58 percent of all lithium atoms found in nature are lithium-7 and 7.42 percent are lithium-6, calculate the atomic mass of lithium, Li (atomic number 3).
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6.942 amu
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Which of the following best describes a conceptual model of an atom?
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a model that illustrates the tendency of an atom to undergo radioactive decay and the products it produces
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Neon, Ne, (number 10) has a relatively large effective nuclear charge, yet it cannot attract any additional electrons because
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its outermost shell is already filled to capacity
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An atom absorbs or emits only particular frequencies of light. White light bends into a glass prism and separates into a rainbow of colors. In which of these two scenarios does the electromagnetic radiation behave as a wave? As a particle?
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Absorption of light shows particle behavior while bending of light shows wave behavior.
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The electron configuration of any neutral group 1 element always ends with
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s1
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The element bromine, Br (atomic number 35), has two major isotopes of similar abundance, both around 50 percent. The atomic mass of bromine is reported in the periodic table as 79.904 atomic mass units. Choose the most likely set of mass numbers for these two bromine isotopes.
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Br-79, Br-81
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Visible light has a frequency range between 7 × 10^14 Hz and 4 × 10^14 Hz. Which frequency of light would have the most energy?
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7 × 10^14 Hz
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Rank the following by relative frequency from highest to lowest:
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gamma rays, blue light, red light, radio waves
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An atomic orbital
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is a region of space where an electron is most likely to be found
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An electron in an outermost shell has more energy than one in an innermost shell because
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it is farther from the nucleus
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An electron de-excites from the fourth quantum level to the third and then directly to the first. Two frequencies of light are emitted. How do their combined energies compare to the energy of the single frequency that would be emitted by de-excitation from the fourth level directly to the first level? Answer: The combined energies of the two frequencies emitted by the one electrons is
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equal to the energy of the single frequency
