Question

Which of the following elements is stable?

A. Carbon, atomic number 6
B. Neon, atomic number 10
C. Fluorine, atomic number 9
D. Boron, atomic number 5

Answer 1

B. Neon, atomic number 10 is the correct answer, because Neon is a noble gas, which already has 8 valence electrons.
Hope this helps~

Answer 2

B. Neon, atomic number 10.