Answer:
A. They are nonreactive gases
Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.
I dont know sorry i wish i could help you
[k]+ [:CL:] -
k has no dots and CL had 8 so 2 on each side of CL and then CL is negative after the closed brackets
