CHEM 1A03 Chapter Notes - Chapter 6: Hong Kong Diploma Of Secondary Education, Lone Pair, Molecular Geometry

• School: McMaster University
• Department: Chemistry
• Course: CHEM 1A03
• Professor: David Brock

Document Summary

Shapes of simple molecules: determined by number of pairs of electrons around central atom (double bonds considered as one pair) Lone pairs: treat lone pairs as bonding pairs when determining shape, except that one of the atoms (the lone pair) will be missing from the 0nal structure. Since lone pairs are closer to the central atom, it pushes the other bonds away and the bond angle is smaller. Ammonia (nh3) has 1 lone pair and 3 bond pairs. It thus has a trigonal pyramidal shape with a bond angle of 107 . Electronegativity: power of an atom to attract bonding electrons in a covalent bond. Trend of electronegativity: top-right atoms are more electronegative. Polar bond: covalent bond between two atoms of di8erent electronegativity such that one atom is slightly positive and the other is slightly negative. Dipole moment: measure of extent of polarization of a bond. Indicated by an arrow from positive atom to negative atom.