Four substituted methane molecules are considered: CH3–H, CH3–F, CH3–Cl
CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Four substituted methane molecules are considered: CH3–H, CH3–F, CH3–Cl, and CH3–Br. A small, qualitative electronegativity scale (in arbitrary units) is provided for reference: H = 2.2, C = 2.5, F = 4.0, Cl = 3.1, Br = 2.8. Answer the following questions about the polarity of each carbon–heteroatom bond.
(a) Order the four C–X bonds (X = H, F, Cl, Br) from least polar to most polar.
(b) Explain your ordering by referring specifically to the periodic trends in electronegativity for the halogens and for hydrogen relative to carbon.
(c) For the most polar of the four bonds, indicate the direction of the bond dipole vector using the symbols δ+ and δ−.