How many hydrogen atoms and how many oxygen atoms are present in a single molecule of water (H_2O)? (Choose the correct pair of numbers for hydrogen and oxygen atoms, respectively.)

• A. 2 hydrogen atoms and 2 oxygen atoms
• B. 2 hydrogen atoms and 1 oxygen atom
• C. 1 hydrogen atom and 1 oxygen atom
• D. 1 hydrogen atom and 2 oxygen atoms

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of water, which is H\_2O.
2. Understand that the subscript number in a chemical formula indicates the number of atoms of that element in one molecule.
3. Look at the subscript for hydrogen (H), which is 2, meaning there are 2 hydrogen atoms in one molecule of water.
4. Look at the subscript for oxygen (O), which is 1 (no subscript means one atom), meaning there is 1 oxygen atom in one molecule of water.
5. Conclude that a single molecule of water contains 2 hydrogen atoms and 1 oxygen atom.