C. Helium is a 'noble' gas, called such because it and the others of it's kind (neon, argon, xenon, etc.) have, as you listed, a full outer electron shell that makes forming and keeping bonds with them very difficult.
Which Of The Following Elements Does Not Form Bonds Easily Because It Has A Full Outer Shell? A. Aluminum B. Carbon C. Helium D. Calcium
B carbon