4.1.1 The Structure of an Atom

• What is the radius of an atom?

  1 x 10^(-10).
• What is the basic structure of an atom?

  A positively charged nucleus composed of both protons and neutrons surrounded by negatively charged electrons laid out in shells.
• What is the radius of a nucleus as a fraction of the radius of an atom?

  1/10000.
• Where is most of the mass concentrated in an atom?

  The nucleus.
• How are the electrons arranged in an atom?

  At different distances from the nucleus in different energy levels (shells).
• What may happen to the electron arrangement of an atom if it absorbs electromagnetic radiation?

  The electrons may move further away from the nucleus into a higher energy level.
• What may happen to the electron arrangement of an atom if it emits electromagnetic radiation?

  The electrons may move closer to the nucleus in a lower energy level.
• Which subatomic particles make up the nucleus of an atom?

  Protons and neutrons.
• What is the charge of an electron?

  -1.
• What is the charge of a proton?

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

  0.
• What is the relative mass of an electron?

  1/1800.
• What is the relative mass of a proton?

  1.
• What is the relative mass of a neutron?

  1.