1.3.3 The development of the neutron model

• What type of particles are emitted by the polonium source in the Chadwick experiment?

  Alpha particles
• What particles were fired at beryllium in the experiment that led to the discovery of the neutron?

  Alpha particles
• Chadwick's experiment was conducted in a vacuum.

  True
• Why was the atomic model incomplete without neutrons?

  Atomic mass was inaccurate
• What type of particles did James Chadwick fire at beryllium in his experiment?

  Alpha particles
• Who discovered the neutron?

  James Chadwick
• The neutral particles released from beryllium were charged

  False
• The mass of a neutron is exactly equal to the mass of a proton

  False
• Neutrons contribute to the stability of the atomic nucleus

  True
• What material was used to detect the release of protons in the experiment demonstrating the neutron's nature?

  Paraffin wax
• What material did Chadwick use to demonstrate that the released particles could eject protons?

  Paraffin wax
• Why did the discovery of the neutron solve the earlier puzzle about missing atomic mass?

  It accounted for neutral mass
• What neutral particle did Chadwick's experiment provide strong evidence for the existence of?

  Neutron
• What type of particles are emitted by the polonium source in the Chadwick experiment?

  Alpha particles
• Chadwick's findings proved that the neutral particles were gamma rays.

  False
• What particles did adding to the atomic model help us understand better?

  Neutrons
• The presence of neutrons creates different isotopes of an element

  True
• What does the number of neutrons determine in an atom?

  Isotopes
• How did Chadwick calculate the mass of the neutron?

  Analyzing interactions with materials
• The absence of neutrons in early atomic models explained atomic mass accurately

  False
• How do neutrons stabilize the nucleus?

  By balancing forces
• What type of particles did Chadwick's experiments confirm the existence of?

  Neutral particles