Atoms

• What does the atomic number indicate?

  It indicates the number of protons.
• Why do atoms of different elements have different atomic numbers?

  Because they have different numbers of protons.
• What is the mass number of an atom?

  The total of protons and neutrons.
• How do you find the number of neutrons in an atom?

  Subtract the atomic number from the mass number.
• What is the charge of a neutral atom?

  Neutral atoms have no overall charge.
• How does the charge of electrons compare to protons?

  Electrons have the same charge size but opposite.
• What happens to an atom when electrons are added or removed?

  It becomes charged and is then an ion.
• What are the three subatomic particles in an atom?

  • Protons
  • Neutrons
  • Electrons
• What is the charge and mass of protons?

  Protons are positively charged and heavy.
• What is the charge and mass of neutrons?

  Neutrons are neutral and heavy.
• What is the charge and mass of electrons?

  Electrons are negatively charged and very light.
• What is relative mass in atomic mass units?

  • Measures mass on a scale
  • Proton or neutron mass is 1
• What is the relative mass of a proton?

  1 atomic mass unit
• What is the relative mass of a neutron?

  1 atomic mass unit
• What is the relative mass of an electron?

  0.0005 atomic mass units
• What is the relative charge of a proton?

  +1
• What is the relative charge of a neutron?

  0
• What is the relative charge of an electron?

  -1