Question

Which of the following molecules does not exist? 1

(a) NF3 (b) NF5 (c)PF5 (d) N2H4​

Answer 1

Answer:

NF5

Explanation:

It has 3 electrons in 2p orbital. Since there is no vacant 2d orbital (which is also not possible,it does not exist) to complete it's octet , that means to expand so N can only form NF3 not NF5.

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Answer 2

(b) NF5 -  molecules does not exist

Except for nitrogen and bismuth, all elements in the fifth group, particularly pentafluorides, produce pentahalides. As previously stated, nitrogen cannot create pentahalides because it lacks the capacity to extend its octet due to the lack of d-orbitals.

Because nitrogen does not have a 3d orbital in its electronic structure, it cannot increase its valency to 5 and so cannot form NF5.

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