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11 Nov 2019
For each of the following transformations: a) draw out the Lewis structures of molecules written as condensed formulas, b) fill in any missing lone pairs of electrons c) identify atoms bearing a partial positive charge d) identify the nucleophile atom (Nue) and the electrophilic (E) atom and (e) fill in the arrows that would lead to the products shown in a single step. An example has been given below. Notice a few things: It is necessary to draw out the Lewis structure of the reagents in order to understand the true reactivity of each molecule-including(especially?) ionic compounds. Remember Na^+ and K^+ (or any other positively charge ions from 1st or second row in periodic table) are spectator ions and will not participate in covalent bond formation, etc, and therefore you should not draw arrows from or to Na^+ or k^+. The arrows begin at the nucleophile atom (Nuc) = Lewis base = source of electrons (lone pairs, pi electrons ,less frequently, very infrequently a sigma bond) The arrows end at the electrophilic atom (E^+) = Lewis acid = electron deficient site (most often, but not exclusively H or C) The charge is conserved on each side of the reaction arrow. If a bond is made to an atom that already has 8 electrons (or 2 in the case of H) a bond must be broken so as not to break the octet rule. Arrows are NOT used to signify formation of IONIC bonds - only covalent bonds. If you have a strong acid present, proton transfer is most likely. If not, use the charges on the molecules to find the strongest Lewis acid or base.
For each of the following transformations: a) draw out the Lewis structures of molecules written as condensed formulas, b) fill in any missing lone pairs of electrons c) identify atoms bearing a partial positive charge d) identify the nucleophile atom (Nue) and the electrophilic (E) atom and (e) fill in the arrows that would lead to the products shown in a single step. An example has been given below. Notice a few things: It is necessary to draw out the Lewis structure of the reagents in order to understand the true reactivity of each molecule-including(especially?) ionic compounds. Remember Na^+ and K^+ (or any other positively charge ions from 1st or second row in periodic table) are spectator ions and will not participate in covalent bond formation, etc, and therefore you should not draw arrows from or to Na^+ or k^+. The arrows begin at the nucleophile atom (Nuc) = Lewis base = source of electrons (lone pairs, pi electrons ,less frequently, very infrequently a sigma bond) The arrows end at the electrophilic atom (E^+) = Lewis acid = electron deficient site (most often, but not exclusively H or C) The charge is conserved on each side of the reaction arrow. If a bond is made to an atom that already has 8 electrons (or 2 in the case of H) a bond must be broken so as not to break the octet rule. Arrows are NOT used to signify formation of IONIC bonds - only covalent bonds. If you have a strong acid present, proton transfer is most likely. If not, use the charges on the molecules to find the strongest Lewis acid or base.
Reid WolffLv2
24 Apr 2019