Why is Lithium a stronger reducing agent than Caesium?

Question

I don't understand, isn't Cs farther from the nucleus and has only 1 valence electron?

Answer 1

Good reducing agents have small ionization energies and low electro-negativities.

 

Based on periodic table trends it would seem that Cs is a better choice then Li. However, from my understanding due to Lithium's size (much smaller then Cs or Na for example) it has a lower charge density.

 

Lower charge densities result in lower negative electrode potential and is chosen because its ions move in and out easily.

 

Lithium has the lowest reduction potential in the electrochemical series.