To determine which molecules are held together by covalent bonds, we need to understand the nature of covalent bonding. Covalent bonds typically form between nonmetals by sharing electrons. Let's analyze each molecule:
1. Oxygen (O₂):
- Oxygen is a diatomic molecule where two oxygen atoms share electrons to achieve a stable configuration. Since both atoms are nonmetals and share electrons, O₂ is definitely held together by covalent bonds.
2. A diamond (C):
- Diamond is a form of carbon where each carbon atom forms four covalent bonds with other carbon atoms in a tetrahedral structure. Thus, a diamond consists of carbon atoms held together by covalent bonds.
3. Ozone (O₃):
- Ozone consists of three oxygen atoms sharing electrons. Like O₂, this is a covalent molecule because the oxygen atoms share electrons with each other.
4. Sodium Chloride (NaCl):
- Sodium chloride is composed of sodium (a metal) and chlorine (a nonmetal). This compound is held together by ionic bonds, where sodium donates an electron to chlorine, resulting in positive sodium ions (Na⁺) and negative chloride ions (Cl⁻) attracting each other.
5. Water (H₂O):
- Water is made of two hydrogen atoms and one oxygen atom. In this molecule, electrons are shared between hydrogen and oxygen atoms, forming covalent bonds.
Based on the analysis:
- Oxygen (O₂)
- A diamond (C)
- Ozone (O₃)
- Water (H₂O)
All of these have molecules held together by covalent bonds. Sodium chloride (NaCl) does not, as it is held together by ionic bonds.
Thus, the covalent molecules are:
- Oxygen (O₂)
- A diamond (C)
- Ozone (O₃)
- Water (H₂O)
