In a chemical reaction, water decomposes to form hydrogen and oxygen. which term names the water? a. an element b. an atom c. a product d. a reactant

The term that name the water in a chemical reaction that water  decomposes is.

  reactant ( answer D)

Explanation

Reactant is a substance  that take part in and undergoes change  during a reaction.   In other  words reactant  are consumed to form product.

water  is   reactant when it decomposes because  it is consumed  to form  hydrogen and oxygen.

The decomposition  of water  is as below  equation,

2H2O→ 2 H2 + O2

atomic number of carbon is 6

electronic configuration of carbon is 1s²2s²2p²

orbital diagram of c is as shown here in the image.