For most atoms, when does the configuration of electrons make the atom unreactive?

• A. When the atom has as many protons as neutrons
• B. When the atom has moved all its electrons to its outermost shell
• C. When the atom achieves a zero net charge
• D. When the atom has eight electrons in its outermost shell

Answer: (D)

Verified step by step guidance

1. Understand the concept of electron configuration: Atoms are made up of protons, neutrons, and electrons. Electrons are arranged in shells around the nucleus, and the outermost shell is known as the valence shell.
2. Learn about the octet rule: Most atoms are stable and unreactive when they have eight electrons in their valence shell. This is known as the octet rule, which is a key principle in chemistry.
3. Identify the noble gases: Noble gases, such as helium, neon, and argon, naturally have a full valence shell, making them unreactive. They serve as examples of atoms that follow the octet rule.
4. Distinguish between the options: Analyze each option given in the problem. The first option relates to the number of protons and neutrons, which affects atomic mass, not reactivity. The second option suggests moving all electrons to the outer shell, which is not feasible. The third option refers to net charge, which is not directly related to electron configuration.
5. Conclude with the correct condition: The correct condition for an atom to be unreactive is having eight electrons in its outermost shell, as this configuration provides stability according to the octet rule.