Chapter 14 Review

Video Review

Key Concept Summary

TA Summary


Dense, positively-charged center of the atom.
Rutherford Model.
Spectra in which only certain specific colors are present.
Thomson Model.
Positively charged particle emitted by some radioactive materials (a helium nucleus).


The electron has no mass.
The red photons found in the emission spectrum of atomic hydrogen are less energetic than the violet photons.
The rare, backward reflection of alpha particles convinced Rutherford that the atom consisted of a dense, positively-charged nucleus.
In gas discharge tube experiments, positive fragments from different types of atoms are similar to one another.
To explain the continuous spectrum of hot objects, Planck proposed that light could only be absorbed or emitted in discrete amounts.
Bohr failed to explain why an accelerated electron does not radiate energy.
Rutherford fully expected alpha particles to bounce off of the gold foil.
The nucleus of an atom occupies more than half of the atom's volume.
The color of a hot object is related to its temperature.


Thompson's gas discharge experiments provide direct experimental evidence for the
In the Thomson (plum pudding) model of the atom, an atom is described as
In what model do electrons orbit the nucleus so that any orbit allowed by Newtonian physics can be occupied by an electron? (i.e., there are no restrictions on allowed electron energies.)
White light (containing all visible colors) passes through a gas that absorbs some of the light. The spectrum of light that passes through the gas is then analyzed. That spectrum could best be described as
Gases emit light when they are energized by an electrical discharge. The light results when an electron
Which of the following models of the atom is correct?
What determines the color of the lines in an atomic emission spectrum?
Hydrogen has one electron. Why does its emission spectrum have four lines?
An electron has a charge of 1.6×10-19 C. Can you cut an electron in half and get a particle with charge 0.8×10-19 C?
The oil drop experiment measured:
Which experiment demonstrated that atoms were made up of positive and negative pieces?
Which model of the atom pictured electrons as orbiting the atom's nucleus like planets orbit the sun?
Does the Bohr model of the atom accurately predict atomic emission spectra?
According to the Bohr model of the atom, how many energy levels does a hydrogen atom have?
If an excited hydrogen atom has its electron in the 3rd energy level, what will happen?

Free Response

  1. What role did Rydberg’s formula play in the development of Bohr’s model?
  2. Use a qualitative (no numbers needed) timeline to map out the sequence of events (experiments) and models that led to the Bohr model.
  3. Use the laws of force and motion to explain Rutherford’s hypothesis (alpha particles would travel in either straight lines or experience small deflections on passing through the gold foil) based on the Plum Pudding Model. Use these same laws to explain why the results of the gold foil experiments ruled out this hypothesis and required the existence of a dense, small, positively-charged nucleus. (It is the logic of Rutherford’s arguments that we are most interested in. You need not give equations.)
  4. How can a continuous spectrum be made up from discrete amounts of energy? What role does the size of Planck’s constant h play in your answer?
  5. What is the relationship between the frequencies present in an emission spectrum and those missing in an absorption spectrum? What law(s) require that there be this type of correspondence?
  6. The absorption spectrum at the bottom of this figure was obtained from an unknown material in the gas discharge tube. Compare the absorption spectrum with the known emission spectra for sodium, mercury, and neon gases and identify the unknown specimen.