Question

which of the following makes up a molecule of water?
o one atom of hydrogen and one atom of oxygen
o one atom of sodium and one atom of chlorine
o one atom of hydrogen and two atoms of oxygen
o two atoms of hydrogen and one atom of oxygen

Explanation:

Step1: Recall the chemical formula of water

The chemical formula of water is \(H_2O\).

Step2: Analyze the formula

In \(H_2O\), the subscript \(2\) indicates there are two hydrogen (\(H\)) atoms, and the subscript \(1\) (usually omitted) for \(O\) indicates one oxygen (\(O\)) atom.

Answer:

One atom of oxygen and two atoms of hydrogen make up a water molecule. So the answer is "two atoms of hydrogen and one atom of oxygen".