Electronegativity and bond polarityEdexcel A-Level Chemistry: Mind map

Exam questions on Electronegativity and bond polarity

1. A chemist compares the hydrogen halides. The Pauling electronegativity values are: H 2.1, F 4.0, Cl 3.0, Br 2.8 and I 2.5.
   Explain why the bond in hydrogen fluoride is polar.2 marks
2. Some Pauling electronegativity values are: Na 0.9, Mg 1.2, Al 1.5 and Cl 3.0. A student compares the bonding in the chlorides NaCl, MgCl₂ and AlCl₃.
   Explain what is meant by saying that ionic and covalent bonding are the extremes of a continuum, using the bonding in aluminium chloride as an example.2 marks
3. A teacher brings a charged plastic rod close to a thin stream of liquid running from a burette. The streams of water and trichloromethane, CHCl₃, are deflected towards the rod. The streams of tetrachloromethane, CCl₄, and hexane are not deflected. The Pauling electronegativity values are: H 2.1, C 2.5 and Cl 3.0.
   Explain why tetrachloromethane is not deflected even though it contains polar bonds.3 marks