普化 有關於鍵結性質

The answer is : (B)

(A) incorrect
The covalent bond joins two F atoms. The two F atoms have the same electronegative.In other words, the two F atoms have equal tendency to attract the bond pair ofelectrons. Hence, the bond pair of electrons is equally shared by the two Fatoms.

(B) correct
In a non-polar covalent bond, the centre of positive charge and the centre ofthe negative charge are coincident. In other words, the bond pair of electronsis equally shared by the bonding atoms.

(C) incorrect
Refer to (B). When the bond pair of electrons is equally shared by bonding atoms,the covalent bond is non-polar, but NOT polar.

(D) incorrect
In a hydrogen bond, the rather "bare" H atoms attract the lone pair ofelectrons, and thus the bond pair of electrons is NOT equally shared.