Atomic Structure

• Wave - Mechanical Model (electron cloud):

  • Based on matter and energy, Electrons move so quickly that we can't tell where they are.
  • Orbitals were renamed as clouds
  • Some areas of the cloud could have a higher probability of having electrons.
• Electron Configurations of Elements:

  • Electrons are configurated by atomic number or protons.
  • The number of electrons are always equal to the number of protons.
• Energy of Electron Levels:

  • Energy Levels are based by it's period or row on the periodic table
  • The energy level are determined by the number of levels they have.
  • As the energy levels are further by the nucleus they become larger, can hold more electrons, and have more potential energy.
• Composition of the Atom:

  • Atoms are made of smaller particles called subatomic particles
• Proton:

  • positively charged
  • mass of 1 atomic mass unit
  • found in nucleus
  • determines the identity of the atom
• Neutron:

  • neutral charge
  • mass of 1 amu
  • found in the nucleus
  • keeps the protons from repelling each other
• Electron:

  • negatively charged
  • mass of 1/2000 amu
  • found in electron clouds/energy levels
  • determines the behavior of atoms
• Atomic Number:

  • number of protons in an atom
• Isotopes:

  • atoms of the same element, each with a different number of neutrons
  • the mass number is the sum of the number of protons and neutrons. (Whole Number).
• Determining the number of neutrons:

  mass number - atomic number = neutrons
• Determining the mass number:

  number of neutrons + atomic number = mass number