Catalyst

							Bell Ringer 11-4-10
1.   Which question(s) did you find difficult on
     the test yesterday?

2.   Today you will write about one page of
     Cornell notes, then you will need a
     separate sheet of paper for an exit slip.
What we’ve learned so far…
   Atoms are made of protons, neutrons and
    electrons
   Protons determine the identity of the element
   Neutrons determine the isotope
   Protons and neutrons are located in the nucleus
    of the atom

        …but what about those electrons?
Electrons in the
Atom
November 4, 2010
Rutherford’s model of the atom:
                 Discovered:
                  Atom is mostly
                   empty space
                  Atom has a small,
                   positively charged
                   center (nucleus)
                  Problems:
                    How  are electrons
                     arranged?
                    Why don’t electrons
                     crash into the
                     nucleus?
How Does a Satellite Stay in Orbit?
    Bohr Model
   Electrons are arranged into
    specific orbitals around the
    nucleus
   Electrons have different
    amounts of energy depending
    on the orbital they are in
   Further away from nucleus =
    more energy
   Closer to nucleus = less
    energy
Check for Understanding:
In your notes: rank the following electrons
  from lowest energy to higher energy
                        1       Energy increases
4
                                as you move AWAY
                                from the nucleus



                                 431 2
3                           2
    Electrons can move!
 Atoms can absorb
  energy or emit energy
 Absorb energy 
  electrons move to higher
  orbitals
 Release energy 
  electrons move to lower
  orbitals
    Light
   Energy absorbed/released by atoms can
    be in the form of light



 Colors of light: ROY G. BIV
 Red = lower energy
 Violet = higher energy
Energy Travels in Waves
How are atoms different?
   Atoms of different elements have orbitals of different
    energies.
   This means they can give off different colors of light!




Atomic emission spectrum: the unique pattern
of light emitted by a specific atom
Check for Understanding
The atomic emission spectrum of an atom is given
  below. Identify which element it is in your notes
  using the known spectra below.
                                           Which element
                                           am I???

        Krypton                     Helium




        Hydrogen                   Xenon
 How do scientists know what stars are
 made of?
    Stars are far away and extremely hot, so we
     can’t take direct samples of gas!
    Scientists look at the light given off by the star
                                           Spectrum of
                                           light from the
                                           Sun

                                           neon


hydrogen                                          helium
Exit Slip
For credit today, copy and complete the following questions
    on a separate sheet of paper using your notes:

1.   Electrons are arranged in ____________ around the
     nucleus.
2.   How does the energy of orbitals change as you move
     away from the nucleus?
3.   Atoms _____________ energy when electrons move
     to higher orbitals.
4.   Atoms _______________ energy when electrons
     move to lower orbitals
5.   Purple light is __________________ in energy than
     red light.
6.   What is an atomic emission spectrum?