CHEM 110 Lecture Notes - Vsepr Theory, Pseudoscience, Ab4

• School: McGill University
• Department: Chemistry
• Course: CHEM 110
• Professor: Ariel Fenster

Document Summary

Exceptions to the octet rule: incomplete octet, incorrect formal charge, expanded octet (extra electrons go to the d orbitals, paramagnetic species (odd number of electrons) Molecules adopt the geometry which maximizes the distance between electron pairs around a central atom, and thus minimizes electrostatic repulsions. Bond length: the distance between atoms a distance b. Bond angles: the angles between the bonds joining different atoms. Molecules containing only bonding pairs around the central atom the shape depends only on the number of electron pairs. Molecules containing both, bonding and lone pairs, around the central atom the shape depends on the respective number of pairs and their position. Lone pairs (l. p) are not as localized as bonding pairs (b. p) and thus cause stronger repulsions: Order of repulsion interactions: l. p l. p > l. p b. p >b. p b. p. ?1. 1. linearlinear2. 2. trigonal planar trigonal planar 33tetrahedraltetrahedral linear trigonal planar tetrahedral trigonal bipyramidal octahedral0%0%0%0%0%:053. 3. tetrahedraltetrahedral4. 4. trigonal bipyramidaltrigonal bipyramidal5. 5. octahedraloctahedralbecl2lewis structure:::::::beclcltwo electron pairs around belinear moleculeoctober 10th, 2011.