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AWESOME. Quantum Mechanical Model. February 28, 2007 Chem 102B. 1s Orbital ( ). Probability of electron in 3-D space around the nucleus. More “s” orbitals. The higher the energy level, the larger the size, and the more nodes that are present Note the Nodes. Nodes.
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AWESOME Quantum Mechanical Model February 28, 2007 Chem 102B
1s Orbital () • Probability of electron in 3-D space around the nucleus
More “s” orbitals • The higher the energy level, the larger the size, and the more nodes that are present • Note the Nodes
Nodes • Region of zero probablity
“P” Orbitals • Dumbell shapes • Sets of 3
Quantum Numbers • n - principalSize and Energy • integer values • l - angularShape • integral values from 0 to n-1 • ml - magneticOrientation • integral values from -l to l including 0 • ms - spinSpin • +1/2 or -1/2
Pauli Exclusion Principle • Two electrons in the same orbital have opposing spins • In a given atom: No two electrons can have same QN’s!
Aufbau Principle • “Building up” • Add electrons one at a time • Energy tells us what order to fill the electrons in the orbitals - Hund’s Rule • Lowest energy equals max number of “unpaired electrons”
Ionization Energies • Energy required to completely remove an electron from an atom.
Electron Affinity • The energy change associated with the addition of an electron to a gaseous atom • X(g) + e- X-(g) • Atoms that tend to form negative ions release more energy when an electron is added
Atomic radius • Half the distance between the nuclei in a molecule consisting of identical atoms • Not exact measure!
Radii trends • Down the group the atoms get larger, more electrons, bigger size. • Across the period the atoms get smaller, why?
R Summary of Trends Too erratic to predict IE EA