Review: What kind of bond is most likely to form between the following? \( \begin{array}{ll}\text { 1. Sodium and chlorine: } & \text { 3. Carbon and oxygen: } \\ \text { 2. Carbon and hydrogen: } & \text { 4. Oxygen and oxygen: }\end{array} \)

To determine the type of bond that is most likely to form between the given pairs of elements, we need to consider their electronegativities and the nature of the elements involved (metals vs. nonmetals). 1. **Sodium and Chlorine:** - Sodium (Na) is a metal, and chlorine (Cl) is a nonmetal. - Sodium has a low electronegativity, while chlorine has a high electronegativity. - The difference in electronegativity is significant, leading to the transfer of an electron from sodium to chlorine. - **Type of bond:** Ionic bond. 2. **Carbon and Hydrogen:** - Both carbon (C) and hydrogen (H) are nonmetals. - They have similar electronegativities, which allows them to share electrons rather than transfer them. - **Type of bond:** Covalent bond. 3. **Carbon and Oxygen:** - Carbon (C) and oxygen (O) are both nonmetals. - They have different electronegativities, but the difference is not large enough to form an ionic bond. - They typically share electrons, forming a covalent bond. - **Type of bond:** Covalent bond. 4. **Oxygen and Oxygen:** - Both atoms are oxygen (O), which is a nonmetal. - Since they are the same element, they will share electrons equally. - **Type of bond:** Covalent bond (specifically, a diatomic molecule). In summary: - Sodium and chlorine: **Ionic bond** - Carbon and hydrogen: **Covalent bond** - Carbon and oxygen: **Covalent bond** - Oxygen and oxygen: **Covalent bond**