Models of The Atom


True/False

  1. Cathode rays are bent by magnetic or electric fields.

  2. All isotopes of hydrogen have one proton in the nucleus.

  3. A proton and a neutron have approximately the same mass

  4. Alpha particles are attracted to the nuclei of atoms.

  5. All isotopes of any one element exhibit essentially the same chemical properties.

  6. The mass of an atom is mostly in the nucleus.

  7. The mass number is the sum of the number of protons and the number of neutrons in an atom.

    Bohr's model of the atom explained the spectra of the hydrogen atom.

  8. In the Bohr model of the atom, an electron gives off energy as it changes from the 2nd to the 4th energy level.

  9. The Heisenberg uncertainty principle states that it is impossible to know both the position and path of an electron.

  10. The 3s orbital is spherical.

  11. There are nine different sub-orbitals in the 3rd energy level.

  12. It is impossible to have a p-type orbital in the second energy level.

  13. When writing electron configurations, the 4s orbitals fill before the 3d orbitals.

  14. Noble gases are stable because their outer-level s, p, and d levels are completely filled.

  15. An Al atom has a larger radius than an Al3+ ion.

  16. Sodium has a low first ionization energy compared to other elements in its period.

  17. A Ne atom has a larger atomic radius and a larger ionization energy than an Ar atom.

  18. The reaction that represents the ionization energy of an F atom is: F (g) + e- Energy + F- (g).

Multiple Choice (Choose the best answer.)

Consider the three statements below in answering questions 1 & 2.

I. Atoms of one element cannot be changed into atoms of another element.
II. Atoms are not created or destroyed in chemical reactions, only rearranged.
III. Atoms contain negative charges embedded in a "dough" of positive charge.

  1. Which statement(s) were part of Dalton's early model of the atom?

    I only

    II only

    III only

    I & II only

    I, II, & III

  2. Based on experiments with cathode ray tubes, Thompson modified Dalton's model of the atom. Which statement(s) represent Thomson's modification?

    I only

    II only

    III only

    I & II only

    I, II, & III

  3. Identify the FALSE statement about Rutherford's "gold foil" experiment.

    Neutral helium atoms were used as "bullets."

    The results were interpreted to mean most of the gold foil was empty space.

    It established the notion of a nuclear atom.

    Alpha particles were repelled by protons in the nucleus.

    Rutherford's model did not explain why electrons orbited the nucleus.

  4. is an isotope of carbon that has a nucleus containing:

    14 neutrons and 6 protons

    6 neutrons and 14 protons

    8 neutrons and 6 protons

    6 neutrons and 8 protons

    None of these.

  5. Which of the following statements about isotopes is FALSE?

    Different isotopes of the same element can have different half-lives.

    Different isotopes of the same element have different numbers of neutrons.

    Bromine atoms with a mass number of 65 contain 30 neutrons.

    The nuclei of all iodine atoms contain 53 protons.

    All isotopes of magnesium contain 24 neutrons.

  6. An element has two naturally occurring isotopes. 80% of the element's atoms have a mass of 17.0 g/mol. 20% of the element's atoms have a mass of 15.0 g/mol. What is the molar mass of the mixture of the isotopes? (All answers in g/mol.)

    15.4

    16.0

    16.6

    32.2

    46.2

  7. When an electron in an atom of hydrogen moves from the second to the first principal energy level, the result is the emission of

    alpha particles

    nuclear mass

    quantized energy

    neutrons

    beta particles

  8. The lowest sub-level in each principal energy level is represented by the symbol:

    f

    p

    s

    d

    g

  9. What is the maximum number of electrons in the "nth" principle energy level?

    n

    2n

    n2

    2n2

    2n3 - 3

  10. Which electron transition is accompanied by the emission of energy?

    1s to 2s

    2s to 2p

    3s to 3p

    4p to 3p

    More than one of these are correct.

  11. Which atom has an electron configuration for its valence shell that is most similar to that of a phosphorus atom?

    N

    Se

    S

    Ar

    F

  12. Which electron configuration corresponds to a nitrogen atom at ground state?

    1s2 2s2p6 3s2

    1s2 2s2p6 3s1

    1s2 2s2p6

    1s2 2s2p5

    1s2 2s2p3

  13. Which of the electron configurations would likely form a -1 ion?

    1s2 2s2p6 3s2

    1s2 2s2p6 3s1

    1s2 2s2p6

    1s2 2s2p5

    1s2 2s2p3

  14. Which of the electron configurations would you expect to have the lowest first ionization energy?

    1s2 2s2p6 3s2

    1s2 2s2p6 3s1

    1s2 2s2p6

    1s2 2s2p5

    1s2 2s2p3

  15. Identify the FALSE statement about orbitals.

    There is one s orbital for each energy level.

    The symbol 4p5 means there are 4 electrons in the 5 p orbitals.

    They are regions of space likely to be occupied by electrons around a nucleus.

    There are four orbitals in the second energy level.

    In each energy level greater than one, there are three p orbitals.

  16. Identify the FALSE statement about this electron configuration:

    [Kr] 5s2 4d10 5p4

    There are four valence electrons.

    It has a similar electron configuration to oxygen.

    It represents Te.

    It likely forms a 2- ion.

    It has 52 electrons.

  17. Which of the following correctly ranks atoms by increasing atomic radius?

    V, Ca, Sr

    Sr, Ca, V

    Ca, V, Sr

    Ca, Sr, V

    None of the above are correct.

  18. Which of the following correctly ranks atoms by increasing ionization energy?

    V, Ca, Sr

    Sr, Ca, V

    Ca, V, Sr

    Ca, Sr, V

    None of these are correct.

  19. Which pair or pair(s) shown below correctly compairs atomic and ionic radii?

    Li < Li +

    N > N 3-

    Cl > Cl -

    More than one of these are correct.

    None of these are correct.

    Problem Solving (Show All Work. Use significant figures)

    1. In his experiments with cathode rays, Thomson found the charge-to-mass ratio for an electron is 1.76 x 108 coulombs/g. In his oil drop experiment, Millikan found the charge of an electron is 1.60 x 10-19 coulomb.

    a) Calculate the mass of a single electron.
    b) Calculate the mass of one mole of electrons.



2. Determine the wavelength, in meters, of the radio signal, KCHM at a frequency of 1510 kilohertz (cycles per second). The velocity of light is 3.00 x 108 m/s.

 

 

3. About 4.2 x 10 5 Joules are needed to break a mole of typical chemical bonds. Would absorption of light having a frequency of 5.2 x 10 14 Hertz be sufficient to break a mole of typical chemical bonds? Planck's constant, h, = 6.63 x 10 -34 (J*sec)/mol.

 

 

 

4. For the atoms shown below:

a) draw an energy diagram

b) write the electron configuration (1s2 2s2 and so on)

c) state the number of valence electrons

d) pick one of the atoms and sketch a picture showing all its orbitals

Na:

 

Na+:

 

S:

Home Page|Homework|Safety Rules|Schedule|Supplies|Tests