Transcript Honors
Honors Material Honors Shapes to Know: – – – – – – – – – – – – Linear Trigonal Planar Bent (with 3 e- regions and with 4) Trigonal Pyramidal Tetrahedral Trigonal Bipyramidal SeeSaw T-Shaped Linear Octahedral Square Pyramidal Square Planar Trigonal bipyramidal electron geometries: • Plane contains three electrons pairs. • Fourth and fifth electron pairs located above and below this plane. HONORS To minimize erepulsion, lone pairs are always placed in equatorial positions. Octahedral electron geometries • Plane contains four electron pairs. • Fifth and sixth electron pairs located above and below plane. Effect of Nonbonding Electrons on Bond Angles – Since electrons in a bond are attracted by two nuclei, they do not repel as much as lone pairs. – Bond angles decrease as the number of lone pairs increase. H C H H H 109.5O N H H H O 107 O H H 104.5O Exceptions to the Octet Rule • Less than Octet – Ex: BeH2 • Odd Number of Valence Electrons – Ex: NO • More than Octet – Ex: SF6 Hybridization of Orbitals • To know hybridization type simply count # of egroups or “domains” around central atom sp = 2 e- domains (linear e- geometry) sp2 = 3 e- domains (trig. planar e- geometry) sp3 = 4 e- domains (tetrahedral e- geometry) sp3d = 5 e- domains (trig. bipyramidal e- geometry) sp3d2 = 6 e- domains (octahedral e- geometry) sp2 sp3 sp3d Resonance • Electrons “resonate” between multiple bonding sites. • Adds strength to all the bonds. • Check if it is possible to draw double or triple bonds at more than one bonding site. Sigma and Pi Bonds • Sigma Bond: – End to end overlap of orbitals – All single bonds are sigma – One of the bonds in a multiple bond is a sigma • Pi Bond: – Side to side overlap of orbitals. – Found in double or triple bonds. Bond Length and Bond Strength • Longest = Single Bonds • Shortest = Triple bonds HONORS Bond Strength • Strongest (hardest to break)= triple bonds • Weakest (easiest to break) = single bonds • VSEPR THEORY (4:51) • https://www.youtube.com/watch?v=keHS-CASZfc • VSEPR Theory (6:30) • https://www.youtube.com/watch?v=Q9-JjyAEqnU • VSEPR SHAPES FOR HONORS: http://youtu.be/FjjhUI4wFTE • Example of Shapes (honors): http://youtu.be/i3FCHVlSZc4 • PHET Model with angles and lone pairs: https://phet.colorado.edu/sims/html/moleculeshapes/latest/molecule-shapes_en.html Honors Good for Review!! • Crash Course Video: Molecular Geometries and Electron Orbitals • http://www.youtube.com/watch?v=cPDptc0wUYI • Orbital Hybridization: (10 min) http://www.youtube.com/watch?v=d1E18tBTlBg