1.  Advanced Chemistry Ms. Grobsky

2.  Bohr’s model was too simple o Worked well with only hydrogen because H only has one electron o Could only approximate spectra of other elements with more than one electron  Electrons do not move in circular orbits  So there is more to the atomic puzzle…

3.  As a result of Planck’s and Einstein’s work, light was found to have certain characteristics of particulate matter o No longer purely wavelike o Waveicle  But is the opposite also true?  A physicist named de Broglie asked the question: Does matter exhibit wave properties?  The answer is Yes! o As shown through X-ray diffraction patterns

4.  Things that are very small behave differently from things big enough to see  Come to find out, electrons bound to the nucleus are similar to standing waves o Standing waves do not propagate through space o Standing waves are fixed at both ends Think of a guitar or violin A string is attached to both ends and vibrates to produce a musical tone Waves are “standing” because they are stationary – the wave does not travel along the length of the string Standing Wave Video

5.  Remember, energy is quantized (i.e. it comes in chunks) o Since the energy of an atom is never “in between”, there must be a quantum leap in energy  Also, a physicist named Heisenberg stated that “[t]here is a fundamental limitation on how precisely we can know both the position and momentum of a particle at a given time” o It is impossible to know both the velocity and location of an electron at the same time

6.  Erwin Schrodinger derived a mathematical equation that described the energy and position of electrons in an atom that became known as the “Quantum Mechanical Model”  An overview of the model: o Electrons are found in energy levels and ORBITALS

7.  Within each energy level, the complex math of Schrodinger’s equation describes several shapes o These are called atomic orbitals Orbitals are NOT circular orbits for electrons Orbitals ARE areas of probability for locating electrons Electron density maps (probability distribution) indicates the most probable distance from the nucleus These DO NOT describe: How an electron arrived at its location Where the electron will go next When the electron will be in a particular location Orbitals of the same shape grow larger as number of energy levels increases # of nodes (areas in which there is zero electron probability) increase as well

8.  With a partner, complete page 204 - “Locating an ‘s’ Electron in an Atom by Analogy” o Be sure the marbles are caught after their first bounce o Be sure marbles are dropped from a consistent height  Change in procedure and data analysis o No carbon paper – you must mark each landing spot with an “X” using a pencil! o Y-axis in graph is (# of dots/cm 2 )*10  Before you begin, do you expect each group to get the same pattern?  Do you expect a marble to land exactly in the middle?

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11.  Follow along on page 205! Atomic Orbitals Java Applet

12. Spherical shape Single orbital Seen in all energy levels Can hold up to 2 electrons

13. p (z) p (y) p (x) x-axis y-axis z-axis Dumbbell-shaped Seen in 2 nd energy level and above Can hold up to 2 electrons PER SUBORBITAL (6 electrons total)

14. Five clover-shaped orbitals Can hold up to 2 electrons per suborbital (10 electrons total) Seen in 3 rd energy level and above

15. Seven equal energy orbitals Each suborbital can hold up to 2 electrons (14 electrons total) Shape is not well-defined Seen in 4 th energy level and above

17.  The orbitals of an atom are LAYERED!