Supplemental packet page 66 Lewis Dot Structures Dr

Supplemental packet page 66 Lewis Dot Structures Dr. Gergens - SD Mesa College

Things to keep in mind when drawing Lewis structure 1. Always count valence electrons 2. Know the preferred number of bonds to these elements CNOFH 4 3 211 3. N O , these elements may have (2) (1) a variable number of bonds (4) (3) 4. If the substance has hydrogen list first in its formula: a. the substance is characterized as an acid b. the H is bound to oxygen in the substance’s structure 5. F O N Cl Br I S C H for determining bond polarity

F O N Cl Br I S C H for determining bond polarity between nonmetal atoms Large difference in electronegativity between H—F most polar bond between C—F very polar bond F O N Cl Br I S C H Little difference in electronegativity Less polar Between identical atoms, C-C, F-F bonding is nonpolar

valence shell electron pair repulsion Ideal bonding for carbon is Four bonds to carbon - Four bonding modes 109. 5 120 120 109. 5 tetrahedral trigonal planar 180 linear Ideal bonding angles for carbon 107. 5 pyramidal or trigonal pyramid 104. 5 bent q<120 bent Bond angles for non-ideal geometries are less than an ideal angle in ideal for C. This is because an electron pair 1) occupies a lot of space & 2) is held close to nucleus of central atom

supplemental HO 70