Question

$PC{l}_5$ is well known but $NC{l}_5$ is not. Because.

• A. nitrogen is less reactive than phosphorous.
• B. nitrogen doesn't have d-orbitals in its valence shell.
• C. catenation tendency is weaker in nitrogen than phosphorous.
• D. size of phosphorous is larger than nitrogen.

Answer 1

Answer: (B)

$PC{l}_5$ forms five bonds by using the d-orbitals to "expand the octet". But $NC{l}_5$ does not exist because there are no $d-$ orbitals in the valence shell ( $2^{\text{nd }}$ shell). Therefore there is no way to expand the octet.