Modern Periodic Table and Periodic Properties — Chemistry STD 10 — Question

When an atom loses an electron/electrons from its valence shell, the element is said to be a reducing agent and the property of the element is called reducing property.
The reducing power of an element depends upon the case with which it can lose electrons. In case of elements at the bottom of a group, the valence electrons are held very loosely by the nucleus. Thus, such elements easily lose their valence electrons and hence have a higher reducing power.