atomic structure

• What do electrons do in an atom?

  They move around the nucleus in electron shells.
• Why do electrons cover a lot of space in an atom?

  Because the volume of their orbits determines the size of the atom.
• What is the charge of an electron?

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

  Very small
• What are all substances made of?

  Atoms
• Why can't atoms be seen with a microscope?

  Because they are too small.
• Where is the nucleus located in an atom?

  In the middle of the atom.
• What particles are contained in the nucleus?

  Protons and neutrons.
• What is the radius of the nucleus?

  $1 \times 10^{-15} \text{ m}$
• Why does the nucleus have a positive charge?

  Because of the protons it contains.
• What is a nanometer (nm) in meters?

  $1 \times 10^{-9} \text{ m}$
• Why is standard form used for large or small numbers?

  To make them easier to understand.
• What is an anion?

  An atom or group of atoms that has lost or gained electrons.
• What is the mass number of sodium (Na)?

  23
• What is the symbol for sodium?

  Na
• Why can't centers be made of atoms?

  Because atoms are too tiny.
• What is the radius of an atom in nanometers?

  About $0.1 \text{ nm}$
• What is the radius of an atom in meters?

  $1 \times 10^{-10} \text{ m}$
• What is the Spanish word for "red"?

  Rojo