Moving from Lewis dot to Structural formula • You have been using Lewis dot structures and molecular formulas • Now we simplify it with structural formulas • Structural formulas use symbols and bonds to show relative position of atoms.
Figuring out number of bonds • Atoms that make the most connections go in the center • Determine the number of electrons available for bonding • Divide that number in half to find the number of bonding pairs • Use as many of your bonding pairs for single bonds • Remaining bonding pairs will make double or triple bonds
Resonance Structures • Resonance is when more than one structure can be written for a molecule or ion.
Exceptions to the Octet rule • Odd numbers of valence electrons • N+O2= how many total electrons? • 5+ 6+6= 17 • They cannot be paired up. • Suboctets • A lone pair of electrons can be shared by a group that doesn’t have a spot • BH3 + NH3
Expanded Octets • When the atom forms more bonds and shares more than eight electrons. • PCl5 • SF6
Naming Electrons • Binary compounds • The first element in the formula is always named first, using the whole element name. • The second element in the formula is named using the root and changing the end to ide. • Prefixes are used to indicate the number of atoms of each element that are present. Ex. Monoxide, dioxide, tetrafloride.
Naming Acids binary • The first word has the hydro to name the hydrogen part of the compound • The rest of the first word consists of a form of the root of the second element plus the suffix –ic. • The second word is acid. • Hydrochloric acid HCl
Naming Acids oxyacids • First indentify the oxyanion present. The first word of an oxyacid’s name consists of the root of the oxyanion and the prefix(if it exists) and the suffix. • Suffix ate is released with ic • ite is replaced with ous • The second word is always acid • Sulfuric acid H2SO4