which of these atoms will release the least amount of energy as the neutral atom gains an electron?\nna + e⁻…

which of these atoms will release the least amount of energy as the neutral atom gains an electron?\nna + e⁻ → na⁻\nli + e⁻ → li⁻\nrb + e⁻ → rb⁻\nk + e⁻ → k⁻

which of these atoms will release the least amount of energy as the neutral atom gains an electron?\nna + e⁻ → na⁻\nli + e⁻ → li⁻\nrb + e⁻ → rb⁻\nk + e⁻ → k⁻

Answer

Answer:

A. $Na + e^- \to Na^-$

Explanation:

Step1: Recall electron - affinity trend

Electron - affinity generally increases across a period and decreases down a group in the periodic table.

Step2: Locate elements in periodic table

$Li$, $Na$, $K$, and $Rb$ are all in Group 1 (alkali metals). $Li$ is in the second period, $Na$ in the third, $K$ in the fourth, and $Rb$ in the fifth.

Step3: Determine electron - affinity order

As we move down Group 1, the atomic size increases, and the effective nuclear charge experienced by the incoming electron decreases. So, the electron - affinity decreases down the group. Among $Li$, $Na$, $K$, and $Rb$, $Na$ has a lower electron - affinity compared to $Li$ and higher than $K$ and $Rb$ among these options, meaning it releases the least energy when gaining an electron compared to the others in the list.