Question 4
Which of these elements exists in nature as single, separate atoms and forms almost no compounds under ordinary conditions?
The right answer is the one marked above.
Neon. Its configuration is 2, 8, so the valence shell is already complete and there is no bonding for it to do.
Sodium (2, 8, 1) and chlorine (2, 8, 7) both have incomplete outer shells and react vigorously. Oxygen is so reactive that it does not even stay as single atoms — it pairs up with itself as O2.