Question

question 4 (2 points)
which of the following is not an exception to the octet rule?
○h
○p
○he
○o

Explanation:

• The octet rule states that atoms tend to gain, lose, or share electrons to have eight electrons in their valence shell.
• H (Hydrogen): Follows the duet rule (wants 2 electrons in its valence shell), so it's an exception.
• P (Phosphorus): Can have an expanded octet (more than 8 electrons) in compounds like \(PCl_5\), so it's an exception.
• He (Helium): Is a noble gas with a full valence shell (2 electrons), but it's a special case as it doesn't follow the octet rule (since it's already stable with 2 electrons), so it's an exception.
• O (Oxygen): Typically follows the octet rule (e.g., in \(H_2O\), \(O_2\) it has 8 valence electrons through bonding or lone pairs).

Answer:

O.