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Subatomic Particles

protons (p+)  

  1. positively charged subatomic particle located in nucleus of an atom

  2. mass = 1.673 E - 24 g   or 1.0073 u

  3. always moving (atomic vibration)

neutrons (n)

  1. subatomic particle located in nucleus that has no electrical charge

  2. mass = 1.675 E - 24 g   or   1.0087 u

  3. free neutron decays into proton, electron, and electron anti-neutrino

  4. half-life of free neutron is about 890 seconds

  5. from Standard Model theory, the neutron is composed of 3 quarks (one Up and 2 Down quarks = UDD), the weak force converts one of the Down quarks into an Up quark, turning the neutron into proton (UUD).  A third particle, known as W boson is emitted as a result of the conversion process.  This W boson decays into an electron and the electron-antineutrino.

  6. The amount of time that a neutron survives before it decays plays a role in determining which elements were created during the Big Bang.  It has a strong influence on the amount of Helium-4 in the universe.

electron (e-)

  1. very small negatively charged subatomic particle found in orbit around nucleus

  2. mass = 1.1 E -29 g     or    0.000 549 u

  3. mass is 1/1836 that of proton

  4. moves very rapidly and is rather easily accelerated

Nucleus has a diameter of about 1 E -14 m, atom has a diameter of about 1 E - 10 m or a difference of 10 000 to 100 000.

Imagine the atom as the size of a professional baseball stadium (in 3D).  The size of the nucleus would be about the size of a baseball in proportion.  Ants would be far too big to represent as the electrons.

Leptons: particles with no perceptible internal structure (and spin 1/2) include the electron neutrino, electron, muon neutrino, muon, tau neutrino, and tau.

Quarks:  particles that make up hadrons.  The 6 quarks in order of increasing size: up, down, charm, strange, top, bottom.

Hadrons:  particles made up of quarks;  examples: protons, neutrons, anti-protons, lambda, and omega

Matter and Antimatter:  for every particle there is a corresponding antiparticle.  These particles and antiparticles have identical mass and spin but opposite charges.

 

Page Last Updated: Friday March 02, 2007           Webmaster: Larry Jones                 Pickens County School District