When are atoms most stable?

• A. When they have the fewest possible valence electrons
• B. When they have the maximum number of unpaired electrons.
• C. When the valence shell is completely full of electrons
• D. None of the above.

Answer: (C)

Verified step by step guidance

1. Understand the concept of valence electrons: Valence electrons are the electrons in the outermost shell of an atom. They play a key role in chemical bonding and stability.
2. Learn about the octet rule: Atoms are most stable when they have a full valence shell, typically consisting of 8 electrons, which is known as the octet rule. This is because a full valence shell resembles the electron configuration of noble gases, which are inherently stable.
3. Consider the electron configuration: Analyze the electron configuration of an atom to determine if its valence shell is full. For example, noble gases like neon and argon have full valence shells, making them very stable.
4. Evaluate the given options: Compare the options provided in the problem. The option stating that atoms are most stable when the valence shell is completely full of electrons aligns with the octet rule and the concept of electron configuration stability.
5. Conclude with the correct understanding: Based on the octet rule and the stability of noble gases, the correct answer is that atoms are most stable when their valence shell is completely full of electrons.