Final answer:
The neutral potassium (K) atom has a more negative electron affinity compared to the potassium ion (K+), since the adding of an electron to the neutral atom releases energy, while additional electrons to the K+ ion would require energy input.
Step-by-step explanation:
Between a neutral potassium (K) atom and a potassium ion (K+), the neutral K atom would have a more negative electron affinity. This is because electron affinity measures the energy change that occurs when an electron is added to a gaseous atom. A neutral atom's electron affinity is typically negative, indicating that energy is released when the atom gains an electron.
However, with a positive ion like K+, the first electron affinity is already satisfied, and any additional electron affinity (such as the second electron affinity) would require energy input, thus being positive or less negative. Therefore, the correct option is A. The neutral K atom has a more negative electron affinity.