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Which element has a complete valence electron shell?

selenium (Se)
oxygen (O)
fluorine (F)
argon (Ar)

User Ukn
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2 Answers

5 votes

Answer:

Answer: argon (Ar)

Step-by-step explanation:

User Deepseapanda
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Answer: argon (Ar)

Ar, Z=18 => 1s2 2s2 2p6 3s2 3p6

The 3 level shell has 8 electrons. The element with one more electron, need to start a new shell to arrange for the last electron.

Argon is a noble gas. Its group in the periodic table is 18. All the noble gases have the last shell full, which conferes them a high stability and low reactivity.
User Akd
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