The correct option is **C. Ionic bond**. ### Explanation of Why the Answer is Correct: 1. **Definition of Ionic Bond**: An ionic bond is formed when one atom transfers one or more of its electrons to another atom. This transfer of electrons leads to the formation of ions: the atom that loses electrons becomes a positively charged ion (cation), while the atom that gains electrons becomes a negatively charged ion (anion). The electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond. 2. **Formation of Ions**: - For example, consider sodium (Na) and chlorine (Cl). Sodium has one electron in its outermost shell (valence shell) and tends to lose that electron to achieve a stable electron configuration (similar to neon, a noble gas). When sodium loses this electron, it becomes a sodium ion (Na⁺). - Chlorine, on the other hand, has seven electrons in its outer shell and needs one more electron to achieve a stable configuration (similar to argon). When chlorine gains an electron from sodium, it becomes a chloride ion (Cl⁻). - The resulting Na⁺ and Cl⁻ ions are then attracted to each other due to their opposite charges, forming the ionic compound sodium chloride (NaCl). 3. **Characteristics of Ionic Bonds**: Ionic bonds typically form between metals and nonmetals. Metals tend to lose electrons and form cations, while nonmetals tend to gain electrons and form anions. Ionic compounds usually have high melting and boiling points, are soluble in water, and can conduct electricity when dissolved in water or molten. ### Explanation of Why the Other Options are Wrong or Weaker: - **A. Covalent bond**: A covalent bond is formed when two atoms share one or more pairs of electrons. This type of bond typically occurs between nonmetals. Since covalent bonds involve sharing rather than transferring electrons, this option does not fit the question's criteria. - **B. Metallic bond**: Metallic bonds occur between metal atoms, where electrons are not transferred or shared in the traditional sense. Instead, they form a "sea of electrons" that are free to move around, which gives metals their characteristic properties such as conductivity and malleability. This option does not involve the transfer of electrons to form ions, making it incorrect. - **D. Hydrogen bond**: A hydrogen bond is a weak attraction that occurs between a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen or nitrogen) and another electronegative atom. Hydrogen bonds are not true bonds in the sense of electron transfer or sharing; they are intermolecular forces. Therefore, this option is also incorrect. ### Summary of Key Points: - An **ionic bond** is formed by the transfer of electrons, resulting in the formation of cations and anions. - Ionic bonds typically occur between metals (which lose electrons) and nonmetals (which gain electrons). - Ionic compounds have distinct properties, including high melting points and electrical conductivity in solution. - Other bond types (covalent, metallic, hydrogen) do not involve the transfer of electrons to form ions, making them unsuitable answers for this question.