Lec 3 Essentials of Chemistry

							Essential Principles of
     Chemistry
        Lecture 3
Generalized Atomic Structure
              Nucleus houses the massive
               particles (protons and neutrons)
                  # Protons = Atomic Number
                  # Protons + Neutrons = Atomic Mass
                  Responsible for mass and density


              Electrons lie in orbitals that
               surround the nucleus
                  # Electrons = # Protons
                     If not, then it is an ION
                  Responsible for bonding
                            Ions
   Ions are electrically charged particles formed by
    the gain or loss of electrons
       Cations are positively charged
       Anions are negatively charged

   Metals are elements that readily form cations

   Non-Metals are elements that readily form
    anions
Electron Orbitals
Alkali Metals
Alkali Earth Metals
Transition Metals
Metaloids
Other Metals
Non-Metals
Halogens
Noble Gases
Decreasing Atomic Radius   Decreasing Atomic Radius
Electronegativity: measure of an atom’s
ability to attract electrons in a chemical bond
Ionic Bonds
         An atom with lower
          electro negativity
          transfers one or more
          electrons to an atom with
          higher electronegativity
            Metal with non-metal


         Results in charged ions

         Oppositely charged ions
          are attracted and thereby
          form a weak bond
Ionic Bonds
         Ions are not actually
          “attached” and so bonds
          are relatively weak
            Soft minerals


         Ions can be attracted by
          other charged ions or
          molecules
            Soluble in water
Covalent Bonds
          Two atoms with
           approximately equal
           electronegativity share
           one or more electrons

          Results in a merging of
           the electron clouds, and
           thereby forms a strong
           bond
             Hard minerals
Metallic Bonds
          Delocalized sharing of
           free electrons among a
           lattice of metal atoms
           with little or no difference
           in electronegativity

          Results in one continuous
           electron cloud
             Soft, malleable
              minerals that conduct
              both heat and
              electricity
Natural Bonds Usually Share
       Characteristics
Van der Waal’s “Bonds”
              Attraction between
               atoms, ions or molecules
               that have an imbalance in
               the distribution of
               electrons (dipole)

              Fleeting and fluctuating
               weak attractions
                 Soft minerals with a
                  low melting point
                 Allows for the basal
                  cleavage in micas