Question

Which compound is likely to have an incomplete octet? which compound is likely to have an incomplete octet? so3 h2s ph3 no?

Answer 1

Nitric oxide (NO) is likely to have an incomplete octet, as the nitrogen atom only has seven electrons in its valence shell, unlike SO3, H2S, and PH3, which adhere to the octet rule.

Step-by-step explanation:

Incomplete Octets in Chemical Compounds

When discussing compounds with possible incomplete octets, Nitric oxide (NO) stands out. Unlike SO3 (sulfur trioxide), H2S (hydrogen sulfide), and PH3 (phosphine), which generally obey the octet rule, NO naturally exhibits an incomplete octet. NO has a total of 11 valence electrons, which results in the nitrogen atom having only seven electrons, making it an odd-electron molecule. This renders NO less stable and highly reactive compared to molecules with complete octets.

Considering the other mentioned compounds, SO3 adheres to the octet rule by having resonance structures that share electrons among the sulfur and oxygen atoms to complete the octet. H2S and PH3 molecules have complete octet configurations as well; however, their focus would be more on their polar character and intermolecular attractions due to differences in melting points as discussed in the review.

Answer 2

Answer:- Octet of NO is incomplete.

Explanations:- For sulfur trioxide, there are total 24 valence electrons. S is the central atom. Two O atoms are bonded to S via single bonds and the third O is bonded to S via double bond. So, in this way, the octet of each O is complete. Total 8 electrons are used in bonding. Each of the single bonded O has three lone pairs and the double bonded O has two lone pairs. It means total 16 electrons are present in the form of lone pairs. The sum of electrons used in bonding and present as lone pairs is 16+8 = 24 and this is exactly same as total valence electrons. So, the octet of S is also complete.

hydrogen sulfide has total 8 valence electrons. H has only one valence electron and can form only a single bond. So, two H atoms are bonded to S via single bonds. Total 4 electrons are used in bonding and remaining 4 electrons are present as two lone pairs on S. So, the octet of S is also complete.

Phosphane has total 8 valence electrons. P is the central atom and the three H atoms are bonded to it via single bonds. Total 6 electrons are used in bonding and rest of the two electrons are present as one lone pair on P. The octet of P is also complete.

NO has 11 valence electrons. Either we make a single, double or triple bond between N and O, the octet for at least one of them is incomplete as there are add number of electrons. The best lewis structure of NO has a triple bond between N and O, 4 electrons around it and N has 3 electrons around it. The octet of O is complete but the octet of N is incomplete as it could complete only 7 electrons.

So, the right answer is NO.

Lewis structures for all the four molecules are given below: