Which of the following elements has the lowest electron affinity?

• A. Ne
• B. Cl
• C. O
• D. F

Answer: (A)

Verified step by step guidance

1. Understand that electron affinity is the energy change that occurs when an atom gains an electron. Elements with higher electron affinity release more energy when gaining an electron, indicating a stronger tendency to accept electrons.
2. Recall the general trend of electron affinity in the periodic table: it tends to increase across a period from left to right and decrease down a group. However, noble gases (Group 18) have very low or positive electron affinities because they have a full valence shell and are very stable.
3. Identify the elements given: Ne (Neon), Cl (Chlorine), O (Oxygen), and F (Fluorine). Neon is a noble gas with a full octet, while Cl, O, and F are nonmetals with incomplete valence shells.
4. Recognize that Neon, having a full valence shell, has a very low (often positive) electron affinity because adding an electron would require placing it in a higher energy level, which is unfavorable.
5. Conclude that among the given elements, Neon has the lowest electron affinity due to its stable electron configuration and reluctance to gain an additional electron.