A chemist is comparing the polarity of several diatomic bonds. A fragment of the chemist’s notes is reproduced below.
Electronegativity values (Pauling scale):
C = 2.5, N = 3.0, O = 3.5, Cl = 3.0, H = 2.1, F = 4.0
Three bonds of interest:
Bond I: N–H
Bond II: C–Cl
Bond III: O–F
Respond to the following.
(a) Calculate the absolute electronegativity difference (∣Δχ∣) for each of the three single bonds listed.
(b) For each bond, indicate which atom bears δ− and which bears δ+. Support each choice with the numerical result from part (a).
(c) Rank the three bonds from least polar to most polar. Provide a short explanation that references your calculations.
(d) Suppose the chemist replaces the chlorine in Bond II with bromine (electronegativity 2.8). Predict how this substitution affects both the assignment of partial charges and the relative position of the new C–Br bond in the ranking from part (c).