Download Chapter 4, Section 1

Chapter 4, Section 1
1. What was the major shortcoming of Rutherford’s model of the atom?
It did not show the locations of the electrons.
2. What was being studied in the early 1900’s that led to a new model of the properties of
atomic particles, energy, and matter? Absorption and emission of light
3. Define electromagnetic radiation.
Form of energy that exhibits wavelike behavior as it travels through space.
4. List 12 examples of electromagnetic radiation. In the text.
5. What is the photoelectric effect? Emission of electron from metal when struck by light.
6. Light is known to be a form of energy, capable of knocking an electron from ametal.
7. Scientists found that even though light was striking a metal, the metal would not exhibit the
photoelectric effect UNLESS the light had a high enough energy which was found to relate to the
light wave’s frequency (number of waves occurring per second). Plank related this
energy to a quantum, the minimum amount of energy trhat can be lost or gained by an atom.
8. Einstein proposed that light waves were made of particles called photons and that
metals must be struck by a single photon that possessed enough energy to knock an electron
loose which could be observed as light energy (different colors of light).
9. Scientists determined that the lowest energy state of an atom is the
ground
state. This is
when its electrons are located in their “normal” expected locations around the nucleus.
10. They also discovered an atom can have an excited state, when it has higher potential energy
and can give off gained energy.
11. When returning to the ground state from its excited state, an atom will give off the energy it
gained in a form of electromagnetic rations, often the production of colored light.
12. Niels Bohr proposed a model of the hydrogen atom to explain its emission of light energy. How
did his model explain atomic structure and electron locations and energy levels?
He said electrons occupy “orbits” around the nucleus. He said they occupy an orbit closest to
the nucleus as possible and that this was the ground state.
13. How did Niels Bohr’s model of the hydrogen atom use the ground state and excited states to
explain the observed spectral lines? He said electrons occupy an orbit in the lowest possible
energy level which is closest to the nucleus. When they gain energy, they “jump” to a higher
energy level farther away from the nucleus. When they fall back to their original ground state,
they release the energy in the form of colored light (spectral lines).