The Lewis structure of Cl2O can be determined by following a few steps. First, we need to calculate the total number of valence electrons in the molecule. Chlorine (Cl) has 7 valence electrons and oxygen (O) has 6 valence electrons. Therefore, for Cl2O, the total number of valence electrons is:
2(7) + 6 = 14 + 6 = 20 valence electrons.
This confirms that statement (a) “Cl2O has 20 valence electrons” is correct.
Next, we will draw the Lewis structure by placing Cl as the central atom, bonded to both Cl and O. The structure would generally involve the central atom (Cl) forming single bonds with the two Cl atoms and one bond with O. To achieve a stable configuration, we would try to complete the octet of the peripheral atoms.
After placing the bonds, we can distribute the remaining electrons to satisfy the octet rule. This leads us to find that the most stable Lewis structure has a total of 10 electrons around the oxygen, which actually violates the octet rule for oxygen. Hence, the statement (b) “the most stable Lewis structure is an exception to the octet rule” is also correct.
Now, since both statements provide accurate observations, it is essential to clarify whether the question is looking for the incorrect statement or an overall assessment of the molecule. If given a choice, the most common confusion lies in understanding that while some Lewis structures may seem stable, not all conform to the conventional octet. Thus, if we think critically about the question, neither statement is technically incorrect; both hold validity in the context of Lewis structures.