it is general information on general chemistry, Schemes and Mind Maps of Chemistry

Download it is general information on general chemistry and more Schemes and Mind Maps Chemistry in PDF only on Docsity! Atomic Theory Exam Name ______________________________ Multiple Choice – 1 pt. each 1) What is the total number of valence electrons in an atom with the electron configuration 2-8-5? a) 2 b) 5 c) 8 d) 15 2) A Ca2+ ion differs from a Ca0 atom in that the Ca2+ ion has a) more electrons b) more protons c) fewer protons d) fewer electrons 3) Which particles are referred to as nucleons (subatomic particles located in the nucleus)? a) protons and neutrons c) neutrons, only b) protons and electrons d) neutrons and electrons 4) What is the mass number of an atom that contains 19 protons, 19 electrons, and 20 neutrons? a) 39 b) 19 c) 58 d) 20 5) What term refers to the region of an atom where an electron is most likely to be found? a) quantum b) spectrum c) orbital d) orbit 6) The nucleus of an atom consists of 8 protons and 6 neutrons. The total number of electrons present in a neutral atom of this element is a) 6 b) 8 c) 2 d) 14 7) What is the maximum number of electrons that can occupy the third principle energy level? a) 18 b) 8 c) 10 d) 3 8) Atoms of 16O, 17O, and 18O have the same number of a) protons, but a different number of electrons c) protons, but a different number of neutrons b) electrons, but a different number of protons d) neutrons, but a different number of protons 9) All atoms of an element have the same a) number of neutrons c) atomic number b) atomic mass d) mass number 10) The atomic number is always equal to the total number of a) neutrons in the nucleus c) neutrons plus protons in the atom b) protons in the nucleus d) protons plus electrons in the atom 11) How many protons are in the nucleus of an atom of beryllium? a) 2 b) 4 c) 9 d) 5 12) Which subatomic particle is negative? a) proton b) neutron c) electron d) nucleus 13) Which of the following particles has the least mass? a) neutron b) proton c) electron d) hydrogen nucleus 14) A sample of element X contains 90% X-35 atoms, 8.0% X-37 atoms, and 2.0% X-38 atoms. The average atomic mass will be closest to which value? a) 35 b) 36 c) 37 d) 38 15) What is the total number of electrons in an Mg+2 ion? a) 10 b) 24 c) 2 d) 12 16) Which of the following electron configurations represents an atom in the excited state? a) 2-8 b) 2-8-1 c) 2-6-1 d) 2-1 17) Which principal energy level of an atom contains an electron with the lowest energy? a) 3 b) 4 c) 1 d) 2 18) The atomic mass of an element is defined as the weighted average mass of that element’s a) naturally occurring isotopes c) radioactive isotopes b) least abundant isotope d) most abundant isotope 19) Compared to the entire atom, the nucleus of the atom is a) smaller and contains most of the atom’s mass c) larger and contains most of the atom’s mass b) smaller and contains little of the atom’s mass d) larger and contains little of the atom’s mass 20) What is the nuclear charge in an atom of boron? a) +11 b) +6 c) +5 d) +12 21) What subatomic particle was discovered in the cathode ray tube experiment? a) proton b) electron c) neutron d) gravitron Short Answer 22) In 1909, a team of British scientists led by Ernest Rutherford, carried out the Gold Foil Experiment to determine the arrangement of particles in the atom. In this experiment, alpha particles were used to bombard gold foil. a) Most of the alpha particles passed through the gold foil undeflected. What conclusion was made about the structure of the atom based on this observation? (1 pt.) b) A few of the alpha particles were deflected back at the source and toward the screen. What did this observation reveal about the structure of the atom? (1 pt.) 23) An element has two isotopes. 90% of the isotopes have a mass number of 20 amu, while 10% have a mass number of 22 amu. Calculate the atomic mass of the element. Show all work with units. (3 pts.)