atoms

• who discovered the electron?

  J.J Thomson (1904)
• who discovered the neutron?

  James Chadwick (1932)
• who discovered the proton?

  Ernest Rutherford (1909)
• who created their atomic model using quantum mechanics?

  Erwin Shrödinger
• what did Neils Bohr change in Rutherford's atomic model?

  Bohr added the concept of electron shells.
• How did Rutherford discover protons?

  Gold foil experiment
• How was the gold foil experiment held?

  Rutherford's gold foil experiment involved firing alpha particles at a thin sheet of gold foil and observing their some of the rays reflect back.
• why did some of the alpha rays in the gold foil experiment reflect back?

  alike charges repel each other
• why did most of the alpha rays in the gold foil experiment pass through?

  the atom is mostly empty space
• what are atoms?

  the smallest piece of matter
• what sub-particles are in an atom?

  Protons, neutrons, and electrons.
• what two sub-particles make up the nucleus?

  Protons and neutrons.
• what electrical charge does a proton have?

  Positive
• what electrical charge does a electron have?

  negative
• what electrical charge does a neutron have?

  no charge