chemistry help?

Question

i am confused why pcl5 exists and ncl5 doesn't?

Answer 1

its because N only has 3 avalbile electrons to bond but P on it's outer has 3 but also contains more electrons at a lower orbit

Answer 2

Well, pcl5 fell out with ncl4. Apparently it was a disagreement over a spare electron. After that, pcl5 simply didn't want to go on, and ncl4 was the last in a long line of casual lovers. So ncl5 never made it!