Which of the following best describes the octet rule?

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

Answer: (D)

Verified step by step guidance

1. Understand that the octet rule is a chemical concept describing how atoms achieve stability by having eight electrons in their outermost shell, known as the valence shell.
2. Recognize that the octet rule explains the tendency of atoms to gain, lose, or share electrons through chemical bonding to complete their valence shell with eight electrons.
3. Note that the octet rule does not relate to the number of protons or neutrons in the nucleus, but rather to the arrangement of electrons around the nucleus.
4. Recall that atoms with a full valence shell of eight electrons are generally more stable, which drives the formation of ionic or covalent bonds.
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.'