Why can calcium act as a reducing agent in chemical reactions?

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A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Calcium acts as a strong reducing agent because its atoms possess two electrons in their outermost s orbital, which are relatively easy to remove. In chemical reactions, calcium readily loses these two valence electrons to achieve a stable electronic configuration similar to that of a noble gas, typically forming a doubly charged ${Ca}^{2 +}$ ion.1

This process of ionization is the defining feature of alkaline-earth metal chemistry. Because calcium can easily donate these electrons to other substances, it effectively reduces them, making it highly useful in industrial applications such as deoxidizing and the production of other metals, including chromium, thorium, and uranium, from their oxides.12