Nonmetals gain electrons under certain conditions to attain a noble gas electron configuration.

1. How many electrons must be gained by the element carbon (C) to attain noble gas electron configuration?

4 electrons.

Explanation:

Carbon must gain four electrons to attain noble gas configuration. Carbon has a total of 6 electrons of which 4 are valence electrons. The four electrons are found in the outermost shell, for a stable configuration Carbon should gain four more electrons to give a 2.8 shell configuration. Most noble gases have 8 electrons in their outer shell with the exception of Helium. By gaining 4 electrons Carbon will have the same shell configuration as Neon.