Size and Mass of Atoms

• What is the approximate radius of an atom?

  About 0.1 nm
• How does the radius of a nucleus compare to that of an atom?

  It is less than 1/100000 of an atom
• What is the approximate radius of a nucleus?

  About 1 x 10^-14 m
• Where is most of an atom's mass located?

  In the nucleus
• What are the relative masses of protons, neutrons, and electrons?

  Proton 1, Neutron 1, Electron very small
• What is the average atomic mass of an element based on?

  Average mass of its isotopes
• How is the average atomic mass calculated?

  By accounting for the relative abundance of isotopes
• What are the key components of atomic structure?

  • Atoms are very small
  • Radius of about 0.1 nm
  • Nucleus is less than 1/100000 of atom's radius
  • Most mass is in the nucleus
  • Protons and neutrons have relative mass of 1
  • Electrons have a very small mass
• What factors influence the average atomic mass of an element?

  • Average mass of isotopes
  • Relative abundance of each isotope
  • Natural occurrence of samples