Which of the following is a correct and balanced equation showing the reaction of calcium and oxygen? (While several of the equations may be balanced, only one has the correct products and reactants as well as being correctly balanced.) A. a. Ca + O2 = CaO B. b. Ca + O2 = CaO2 C. c. 2Ca + O2 = 2CaO D. d. 4Ca + O2 = 2Ca2O E. e. Ca + O2 = Ca2O 26-3.

The correct option is: C. 2Ca + O₂ = 2CaO

Explanation:

Calcium is a s-block element, belonging to the group 2 and period 4 of the periodic table.

It is an alkaline earth metal having 2 valence electrons in its outermost s-orbital. So, calcium generally exists in + 2 oxidation state in its compounds.

When calcium (Ca) reacts with oxygen (O₂), calcium oxide or quicklime (CaO) is formed.

The balanced chemical equation is: 2Ca + O₂ → 2CaO