Lewis structures are represented in different ways in different parts of the world. Two ways of drawing the Lewis structure for ${{\text{H}}_{\text{3}}}{{\text{O}}^ + }$ are shown below.

Which statement is correct about ${{\text{H}}_{\text{3}}}{{\text{O}}^ + }$?

A.     The ion has a tetrahedral shape.

B.     The H–O–H bond angle is 120°.

C.     The H–O–H bond angle is 90°.

D.     The ion has a trigonal pyramidal shape.

D

One respondent stated that as the hydronium cation involves dative covalent bonding it would have been better if the dot-cross representation would have reflected this, which is a valid point. However, this did not stop candidates answering the question and 72.31% of candidates got the correct answer, namely that the ion has a trigonal pyramidal shape i.e. D.