Which of the following is true about how hydrogen and oxygen can combine to form molecules?

• A. Hydrogen and oxygen cannot form stable molecules together.
• B. Two hydrogen atoms and one oxygen atom combine to form H_2O through covalent bonding.
• C. Hydrogen and oxygen combine to form H_2O by ionic bonding.
• D. One hydrogen atom and two oxygen atoms combine to form H_2O_2 through metallic bonding.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the types of chemical bonds. Covalent bonds involve sharing electrons between atoms, ionic bonds involve transfer of electrons creating charged ions, and metallic bonds involve a 'sea' of delocalized electrons typically between metal atoms.
2. Step 2: Recall the molecular composition of water (H_2O). Water consists of two hydrogen atoms covalently bonded to one oxygen atom, forming a stable molecule.
3. Step 3: Analyze the bonding in water. Since hydrogen and oxygen are nonmetals, they form covalent bonds by sharing electrons rather than ionic or metallic bonds.
4. Step 4: Evaluate the incorrect options: hydrogen and oxygen do form stable molecules (so the first option is false), water is not formed by ionic bonding (second option is false), and H_2O_2 (hydrogen peroxide) has a different composition and bonding, and metallic bonding does not occur between hydrogen and oxygen (fourth option is false).
5. Step 5: Conclude that the correct statement is that two hydrogen atoms and one oxygen atom combine to form H_2O through covalent bonding.