Which statement best describes the octet rule?

• A. Atoms with eight electrons in their outer shell are always reactive.
• B. Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.
• C. Atoms form bonds only when they have eight neutrons.
• D. Atoms always have eight protons in their nucleus.

Answer: (B)

Verified step by step guidance

1. Understand that the octet rule is a chemical principle that explains how atoms achieve stability by having eight electrons in their valence (outermost) shell.
2. Recognize that atoms tend to gain, lose, or share electrons through chemical bonds to complete their valence shell with eight electrons, which leads to a more stable electronic configuration.
3. Note that the octet rule applies mainly to main-group elements, especially those in the second period of the periodic table, such as carbon, nitrogen, oxygen, and the halogens.
4. Eliminate incorrect statements: atoms do not always have eight electrons in their outer shell naturally, nor do they form bonds based on the number of neutrons or protons in the nucleus.
5. Conclude that the best description of the octet rule is: 'Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.'