Question

which of these elements has the most unreactive valence electron configuration?
a. ne
b. cl
c. c
d. i

Explanation:

• Ne (Neon): It is a noble gas. Noble gases have a full valence shell (for neon, it has 8 valence electrons in the second shell, following the octet rule). A full valence shell makes the atom very stable and unreactive as it has little tendency to gain, lose, or share electrons.
• Cl (Chlorine): Has 7 valence electrons. It tends to gain 1 electron to complete its octet, so it is reactive.
• C (Carbon): Has 4 valence electrons. It can form various bonds (covalent bonds) by sharing electrons to achieve a more stable electron configuration, so it is reactive.
• I (Iodine): Has 7 valence electrons (similar to chlorine in its group - halogens). It tends to gain 1 electron to complete its octet, so it is reactive.

Answer:

A. Ne