Which is the best definition of electronegativity?

A.     Electronegativity is the energy required for a gaseous atom to gain an electron.

B.     Electronegativity is the attraction of an atom for a bonding pair of electrons.

C.     Electronegativity is the attraction between the nucleus and the valence electrons of an atom.

D.     Electronegativity is the ability of an atom to attract electrons from another atom.

B

With a difficulty index of 24%, this proved to be one of the most challenging questions on the paper and seems to reinforce an impression, also noted elsewhere, that whilst candidates have some general awareness of a concept, they are unable to define it in appropriate detail.