Chem Exam 8 Flashcards
Exceptions to the octet rule
Unpaired electrons.
Molecules, such as NO, with an odd number of electrons;
Molecules in which one or more atoms possess more than eight electrons, such as SF6; and
Molecules such as BCl3, in which one or more atoms possess less than eight electrons.
Bond Dissociation Energy
One measure of the strength of the chemical bond.
Sigma Bonds
First type of covalent bond, formed by an overlap of atomic orbitals head-to-head. They are stronger than pi bonds and can exist independently in single bonds.
Pi bonds
Second and third types of covalent bonds, formed by the overlap of p orbital side by side (only occur in single and triple bonds). Pi bonds must coexist with a sigma bond.
Hybridization
Redistribution of the energy of orbitals of individual atoms to give orbitals of equivalent energy.
Van der Waals Force
A category encompassing the two weakest attractions between molecules.
London Dispersion Force
A Van der Waals force that is the weakest force of all. It’s caused by the motion of electrons in nonpolar molecules.
Dipole-dipole forces
Another Van der Waals that includes forces between polar molecules, similar to ionic bonds, but MUCH weaker.
Hydrogen bonds
A special type of dipole dipole interaction = attractive forces in which a hydrogen is covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom (O,F,N).
Resonance
When there are multiple different forms of a molecule as electron pairs bounce between different outer atoms (in a molecular structure) to keep all of those atoms satisfied.
Naming Molecular Compunds
Write the name for both elements.
Change the ending of the second element to ide.
Place prefixes in front of each element based on the number of atoms present.
The prefix ‘mono’ is only used on the second non-metal in the chemical formula.
There shouldn’t be two vowels in a row.
