Name Atomic Structure Practice Exam Date:

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1 Name Atomic Structure Practice Exam Date: 1. In the late 1800s, experiments using cathode ray tubes led to the discovery of the 1) electron 2) neutron 3) positron 4) proton 2. Which subatomic particles are located in the nucleus of an He-4 atom? 1) electrons and neutrons 2) electrons and protons 3) neutrons and protons 4) neutrons, protons, and electrons 3. Which two particles have opposite charges? 1) an electron and a neutron 2) an electron and a proton 3) a proton and a neutron 4) a proton and a positron 4. The diagram below represents the nucleus of an atom. What are the atomic number and mass number of this atom? 1) The atomic number is 9 and the mass number is 19. 2) The atomic number is 9 and the mass number is 20. 3) The atomic number is 11 and the mass number is 19. 4) The atomic number is 11 and the mass number is Which statement best describes the nucleus of an aluminum atom? 1) It has a charge of +13 and is surrounded by a total of 10 electrons. 2) It has a charge of + 13 and is surrounded by a total of 13 electrons. 3) It has a charge of -13 and is surrounded by a total of 10 electrons. 4) It has a charge of -13 and is surrounded by a total of 13 electrons. 6. Which of the following particles has the smallest mass? 1) neutron 2) electron 3) proton 4) hydrogen atom 7. Which conclusion was a direct result of the gold foil experiment? 1) An atom is mostly empty space with a dense, positively charged nucleus. 2) An atom is composed of at least three types of subatomic particles. 3) An electron has a positive charge and is located inside the nucleus. 4) An electron has properties of both waves and particles. 8. Which sequence represents a correct order of historical developments leading to the modern model of the atom? 1) the atom is a hard sphere most of the atom is empty space electrons exist in orbitals outside the nucleus 2) the atom is a hard sphere electrons exist in orbitals outside the nucleus most of the atom is empty space 3) most of the atom is empty space electrons exist in orbitals outside the nucleus the atom is a hard sphere 4) most of the atom is empty space the atom is a hard sphere electrons exist in orbitals outside the nucleus 9. What can be determined if only the atomic number of an atom is known? 1) the total number of neutrons in the atom, only 2) the total number of protons in the atom, only 3) the total number of protons and the total number of neutrons in the atom 4) the total number of protons and the total number of electrons in the atom 10. What is the total charge of the nucleus of a nitrogen atom? 1) +5 2) +2 3) +7 4) What is the mass number of a carbon atom that contains six protons, eight neutrons, and six electrons? 1) 6 2) 8 3) 14 4) The total mass of the protons in an atom of gold-198 is approximately 1) 79 atomic mass units 2) 119 atomic mass units 3) 198 atomic mass units 4) 277 atomic mass units

2 13. What is the mass number of an atom that has six protons, six electrons, and eight neutrons? 1) 6 2) 12 3) 14 4) What is the total number of neutrons in an atom of 7 3 Li? 1) 7 2) 10 3) 3 4) An atom of helium-4 differs from an atom of lithium-7 in that the atom of helium-4 has 1) one more proton 2) one more neutron 3) two less protons 4) two less neutrons 16. The table below shows the number of subatomic particles in atom X and in atom Z. Atom X and atom Z are isotopes of the element 1) aluminum 2) carbon 3) magnesium 4) nitrogen 17. The table below gives information about the nucleus of each of four atoms. 19. Which subatomic particle is found in the nucleus of all isotopes of hydrogen? 1) proton 2) neutron 3) electron 4) positron 20. Each diagram below represents the nucleus of a different atom. How many different elements are represented by the nuclei in the table? 1) 1 2) 2 3) 3 4) Isotopes of an element must have different 1) atomic numbers 2) mass numbers 3) numbers of protons 4) numbers of electrons Which diagrams represent nuclei of the same element? 1) D and E, only 2) D, E, and Q 3) Q and R, only 4) Q, R, and E

3 21. If 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element? Must show work. 1) 35.0 amu 2) 36.0 amu 3) 35.5 amu 4) 37.0 amu 22. The atomic mass of titanium is atomic mass units. This atomic mass represents the 1) total mass of all the protons and neutrons in an atom of Ti 2) total mass of all the protons, neutrons, and electrons in an atom of Ti 3) weighted average mass of the most abundant isotope of Ti 4) weighted average mass of all the naturally occurring isotopes of Ti 23. What is the total number of valence electrons in an atom of germanium in the ground state? 1) 8 2) 2 3) 14 4) The maximum number of electrons that can occupy a principal energy level (n) of an atom is equal to 1) n 2) 2n 3) n 2 4) 2n An atom of which element in the ground state contains electrons in the fourth principal energy level? 1) Kr 2) Ar 3) Ne 4) He 26. What is the total number of electrons in the second energy shell of a calcium atom in the ground state? 1) 6 2) 2 3) 8 4) Given the bright-line spectra of three elements and the spectrum of a mixture formed from at least two of these elements: Which elements are present in this mixture? 1) E and D, only 2) E and G, only 3) D and G, only 4) D, E, and G

4 28. Which statement describes how an atom in the ground state becomes excited? 1) The atom absorbs energy, and one or more electrons move to a higher electron shell. 2) The atom absorbs energy, and one or more electrons move to a lower electron shell. 3) The atom releases energy, and one or more electrons move to a higher electron shell. 4) The atom releases energy, and one or more electrons move to a lower electron shell. 29. As an electron in an atom moves from the ground state to the excited state, the electron 1) gains energy as it moves to a higher energy level 2) gains energy as it moves to a lower energy level 3) loses energy as it moves to a higher energy level 4) loses energy as it moves to a lower energy level 30. Which electron configuration represents the electrons of an atom in an excited state? 1) ) ) ) Which electron transition represents a gain of energy? 1) from 2nd to 3rd shell 2) from 2nd to 1st shell 3) from 3rd to 2nd shell 4) from 3rd to 1st shell 32. Which is the configuration of an atom in the ground state? 1) ) ) ) What causes the emission of radiant energy that produces characteristic spectral lines? 1) neutron absorption by the nucleus 2) gamma ray emission from the nucleus 3) movement of electrons to higher energy levels 4) return of electrons to lower energy levels 34. Which group of atomic models is listed in historical order from the earliest to the most recent? 1) hard-sphere model, wave-mechanical model, electron-shell model 2) hard-sphere model, electron-shell model, wave-mechanical model 3) electron-shell model, wave-mechanical model, hard-sphere model 4) electron-shell model, hard-sphere model, wave-mechanical model 35. The greatest absorption of energy occurs as an electron moves from 1) 1s to 3s 2) 3p to 3s 3) 4d to 4s 4) 4s to 3p 36. What can be concluded if an ion of an element is smaller than an atom of the same element? 1) The ion is negatively charged because it has fewer 2) The ion is negatively charged because it has more 3) The ion is positively charged because it has fewer 4) The ion is positively charged because it has more 37. What is the net charge on an ion that has 9 protons, 11 neutrons, and 10 electrons? 1) 1+ 2) 2+ 3) 1-4) What is the total number of electrons in a S 2 ion? 1) 10 2) 14 3) 16 4) Which change occurs when a barium atom loses two electrons? 1) It becomes a negative ion and its radius decreases. 2) It becomes a negative ion and its radius increases. 3) It becomes a positive ion and its radius decreases. 4) It becomes a positive ion and its radius increases. 40. Which particle has the same electron configuration as a potassium ion? 1) fluoride ion 2) sodium ion 3) neon atom 4) argon atom 41. What occurs when an atom of chlorine forms a chloride ion? 1) The chlorine atom gains an electron, and its radius becomes smaller. 2) The chlorine atom gains an electron, and its radius becomes larger. 3) The chlorine atom loses an electron, and its radius becomes smaller. 4) The chlorine atom loses an electron, and its radius becomes larger. 42. Which ion has the same electron configuration as an atom of He? 1) H 2) O 2 3) Na + 4) Ca 2+

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