Chem 351: Chapter 1 - Atoms

• Atom


  Has a nucleus at its core and is surrounded by electrons
• Nucleus


  • Comprised of protons and neutrons
• Proton


  Positively charged, +1 unit
• Neutron


  No charge
• Electron


  Much smaller and negatively charged, -1 unit
• Atomic number, Z


  Number of protons in the nucleus of an atom, defines the type of atom
• Mass number, A


  Total number of protons and neutrons in the nucleus
• A neutral atom must have the same number of electrons surrounding the nucleus as there are protons in the nucleus
• Isotopes


  Atoms of the same element with different numbers of neutrons
• The periodic table is arranged based on increasing atomic number
• The mass number, A, from the periodic table is the isotopic mass number or the weighted average of the isotopic masses based on a normal sample
• Elements commonly involved in introductory organic chemistry

  • H
  • C
  • N
  • O
  • Cl
  • Br
  • I
• All matter is composed of atoms
• Atoms


  An ordered collection of various subatomic particles
• Atom


  • Central nucleus contains protons and neutrons
  • Electrons around the nucleus
• Helium atom


  • Nucleus contains 2 protons and 2 neutrons
  • 2 electrons
• You should be familiar with the subatomic particles and how to determine how many of each a specific atom has
• Atoms of greatest interest in introductory organic chemistry

  • H
  • C
  • N
  • O
  • F
  • Cl
  • Br
  • I
  • Li
  • Na
  • Mg
  • Al
  • B
  • P
  • S
• When one probes deeper into more advanced synthetic methods, one needs to be familiar with many more elements
• Atoms


  All matter is composed of atoms
• Atoms


  An ordered collection of various subatomic particles
• Atom


  • Central nucleus contains the protons and neutrons
  • Around the nucleus are the electrons
• Helium atom


  • Nucleus contains two protons and two neutrons
  • Two electrons
• You should be familiar with the subatomic particles and how to determine how many of each a specific atom has
• Atoms of greatest interest in introductory organic chemistry

  • H
  • C
  • N
  • O
  • F
  • Cl
  • Br
  • I
  • Li
  • Na
  • Mg
  • Al
  • B
  • P
  • S