which element has a complete valence electron shell?\no selenium (se)\no oxygen (o)\no fluorine (f)\no argon…

which element has a complete valence electron shell?\no selenium (se)\no oxygen (o)\no fluorine (f)\no argon (ar)

which element has a complete valence electron shell?\no selenium (se)\no oxygen (o)\no fluorine (f)\no argon (ar)

Answer

Answer:

D. argon (Ar)

Explanation:

Step1: Recall valence - shell rules

Noble gases have a complete valence - electron shell.

Step2: Identify noble gas

Argon is a noble gas. Selenium is a chalcogen, oxygen is also a chalcogen, and fluorine is a halogen. Only argon has a complete valence - electron shell with 8 electrons in its outermost shell (a stable octet for a main - group element), following the octet rule for stability.