CK-12-Physics-Concepts - Intermediate

http://www.ck12.org Chapter 23. The Atom

Practice

Questions

http://www.youtube.com/watch?v=hpKhjKrBn9s

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/64136

Follow up questions:

1. Why does the Rutherford planetary model predict that the electron would collapse into the nucleus?


2. Bohr used Planck’s suggestion that energy emitted by matter was not emitted in continuous quantities but in
   _____ bundles.


3. Bohr’s calculations were based on the atoms of which element?

Review

Questions

1. Why did Rutherford suggest that the positive charge in an atomic nucleus is concentrated in a tiny region
   rather than spread evenly throughout the atom?


2. The absorption spectrum of an element has the same frequencies as the emission spectrum. How does Bohr’s
   theory explain this?


3. Why do scientists say the planetary model can’t be correct because the electrons would collapse into the
   nucleus?


4. If you were trying to explain the idea of quantization to younger students, do you think you should use water
   or money as an example? Why?

• scintillation counter: A scintillation counter measures ionizing radiation. The sensor, called a scintillator,
  consists of a transparent crystal or liquid that fluoresces (emits a flash of light) when struck by ionizing
  radiation. A sensitive photomultiplier tube measures the light from the crystal and is attached to an electronic
  amplifier or other electronic equipment to count the signals.


• alpha particles:A positively charged particle, indistinguishable from a helium atom nucleus and consisting
  of two protons and two neutrons


• nucleus:The nucleus is the very dense region consisting of protons and neutrons at the center of an atom.


• nuclear model:The nuclear model of the atom states that the atom consists of a dense positive center called
  the nucleus and is surrounded by negatively charged electrons in an electron cloud.


• quantization:Quantization is the concept that a physical quantity can have only certain discrete values and
  intermediate values are prohibited.