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Surprising Experimental Results. Atomic spectra Atoms are found to give off unique colors of light rather than the rainbow type spectra of a normal light bulb Experiment last class illustrated this. Do you understand this result?. Surprising Experimental Results. BB radiation
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Surprising Experimental Results • Atomic spectra • Atoms are found to give off unique colors of light rather than the rainbow type spectra of a normal light bulb • Experiment last class illustrated this. • Do you understand this result? GSCI 163 Spring 2010
Surprising Experimental Results • BB radiation • Photo-electric effect • … Knowing the problems is irrelevant for this class but recognizing that a new approach was introduced and the consequences of this approach for atoms is essential. GSCI 163 Spring 2010
Add QM • Every atom has a set of energy levels 1,2,3,4... • The levels are made up of orbitals labeled by a convention that we need to learn. • S,P,D,F GSCI 163 Spring 2010
Orbitals 1S 2S 4F 2P GSCI 163 Spring 2010
6 possible transitions each one a different but fixed amount of energy is released or absorbed in order to jump down or up. smallest largest GSCI 163 Spring 2010
Behave like an atom • Throw a ball when you jump down. • Catch a ball to jump up • Ball must match the jump. GSCI 163 Spring 2010
spin • Electrons have a new characteristic SPIN • Spin up • Spin down GSCI 163 Spring 2010
Need to know BUILD PERIODIC TABLE • Light is quantized (orbital jumps) and a particle of light is called photon • Orbital structure and names (previous diagram) 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f • Electron has spin • Pauli exclusion: No two electrons can occupy the same state (orbital) • Spin and Pauli 2 electrons per orbital • Orbitals are grouped into shells • The orbital configuration remains roughly the same for each atom (subtle) so that the shell structure is a general characteristic of all atoms. • Electron configuration is represented as 1s22s22p3 • The last or highest shell for an atom is the valence shell. • The valence shell determines the chemistry and properties. 2s22p3 • This orbital structure has a repeating pattern 2s22p3 3s23p3 4s24p3 5s25p3 B Al Ga In GSCI 163 Spring 2010
Metals • Non-metals • Noble gases • Groups • Periods • Others lanthanoids … GSCI 163 Spring 2010
Noble gases don’t interact • Metals conduct • Nuclear charge (number of protons) • Mass of atoms GSCI 163 Spring 2010
PT atom size GSCI 163 Spring 2010
First Ionization energy required to remove first electron GSCI 163 Spring 2010
Electronegativity & Electron affinity Ability to add an electron Electronegativity TREND Noble gasses do not accept electrons Electron Affinity Measure energy released when electron added GSCI 163 Spring 2010
Periodic Table • What does it tell us about chemistry? • Properties of atoms in the table • From where does this structure come? • Orbital structure and filling GSCI 163 Spring 2010