Unshared, or lone, electron pairs play an important role in determining the chemical and physical properties of organic compounds. Thus, it is important to know which atoms carry unshared pairs. Use the structural formulas below to determine the number of unshared pairs at each designated atom. (Be sure your answers are consistent with the formal charges on the formulas.) The number of unshared pairs at atom a is co The number of unshared pairs at atom b is H3C CH The number of unshared pairs at atom c is The number of unshared pairs at atom a is H,C- The number of unshared pairs at atom b is CH2 The number of unshared pairs at atom c is

Complete the Lewis structure for BrNO2 (N is central). Show resonance structures if applicable.

Write the Lewis symbols for the following neutral atoms: Element Potassium Strontium Sulfur lodine Element symbol Number of valence electrons Lewis dot symbol Write the Lewis dot symbol for the following monoatomic ions: Element Potassium Element symbol for ion Lewis dot symbol for ion Strontium Sulfur lodine

Molecular Shape:trigonal planar Questions: (Complete sentences are not necessary) 1 Examine the Lewis structure for each of the molecular shapes formed above. (ignore BrF!) Complete the following table based upon both the number of unshared electron pairs around the central atom and also the number of bond groups that are around the central atom. For example. in the following Lewis structure of PBr,, phosphonus (the central atom) has one pair of unshared electrons and three bond ypoups surrounding it. :Br: Br (Note: single, double, and triple bonds all count as single bond groups) Number of Bond Groups Number of Unshared Electron Pairs Around the Central Atom Molecular Shape Around Central Atom Linear Bent Trigonal Planar Trigonal Pyramidal Tetrahedral 2. What is the electrostatic charge of all electron groups. either shared (Le. bonds) or unshared? Since all electron groups have this same charge. do they attract or repel each other?