Electron affinities generally become more favorable (more negative) as you move from left to right across a period. However, the electron affinity for Be is less favorable than the electron affinity for Li, as shown below.
Li(g) + e + Li (9) EA = -60 kJ/mol
Be(g) + e + Be (g) EA> 0 kJ/mol
Which of the following best helps to explain why the electron affinity for Be is less favorable than the electron
affinity for Li?