Which one of the following atoms has the least tendency to gain another electron?

• A. Neon
• B. Oxygen
• C. Chlorine
• D. Sodium
• E. Hydrogen

Answer: (A)

Verified step by step guidance

1. Understand the concept of electron affinity, which is the tendency of an atom to gain an electron. Atoms with high electron affinity are more likely to gain electrons.
2. Consider the electronic configuration of each atom. Neon is a noble gas with a full outer shell, making it stable and unlikely to gain additional electrons.
3. Oxygen and chlorine are nonmetals with high electron affinities, as they are close to completing their outer electron shells.
4. Sodium is a metal that tends to lose electrons to achieve a stable electron configuration, rather than gain them.
5. Hydrogen has a single electron and can gain one more to achieve a stable configuration similar to helium, but it is less likely to gain electrons compared to nonmetals like oxygen and chlorine.