Electrons in Atoms

Electrons in Atoms


As you continue your investigation into the history of the atom, you will look at the advancement of atomism since the electron. Use the information from the Electrons in Atoms resource to match these terms.

Directions: Match the terms with their corresponding descriptions from Electrons in Atoms.

1. ___ electron

a.  Discovered by Rutherford in 1911, this is the center of an atom and has a positive charge and carries 99.9% of its mass.

2. ___ proton

b.  Instruments used to count the flashes of charged particles

3. ___ neutron

c.  Discovered by Carl D. Anderson in 1932, this electron with a positive charge is “the antimatter equivalent to the electron.”

4. ___ nucleus

d.  Accelerator first developed by Cockfort and Walton, showed how fast moving protons could cause nuclear disintegrations

5. ___ positron

e.  Discovered by J.J. Thomson in 1897, this particle has a negative charge and is much smaller than atoms.

6. ___ electron tracks

f.   Term proposed by Rutherford in 1920 for hydrogen nuclei, the “building blocks of all nuclei”

7. ___ cyclotron  

g.  Discovered by James Chadwick in 1932, this particle has no electric charge and is found in the nuclei of most atoms.

8. ___ scintillation detectors

h.  By measuring the curvature of these colliding electrons, their energy could be estimated.

9. ___ atom smashers

i.   First built in 1932, this machine was used to accelerate protons in a spiral at high speeds using low voltage.

10. ___ quantum electrodynamics   

j.   Theory describing the behavior of electrons and other electrically-charged particles with considerable accuracy.

11. ___ quarks and leptons

k.  The two sets of particles making up the Standard Model


Directions: Match the figures with their corresponding descriptions from Electrons in Atoms.

1. ___ Wolfgang Pauli

a.  Discovered in 1934 a new type of radioactivity, similar to beta decay but emitted positrons instead of electrons

2. ___ Gell-Mann and Zweig

b.  First split the atom, and used alpha particles to propose a new atomic structure with a tiny solar system with a nucleus and electrons orbiting it

3. ___ George P. Thomson

c.  Suggested that electrons were restricted to orbit the nucleus, and that, when they jumped from one orbit to another, the atom emitted or absorbed light

4. ___ Charles Wilson

d.  Discovered the neutrino in 1930, a lighter neutral particle in a nucleus

5. ___ Curie and Joliot

e.  Instrumental in demonstrating the wave properties of electrons, which could sometimes behave like electromagnetic waves, like visible light

6. ___ Ernest Rutherford

f.  First used cloud chambers and photograph tracks of electrons being released when exposed to X rays

7. ___ Niels Bohr

g.   Theorized quarks by grouping together and comparing different particles


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