Kaplan Nursing Entrance Practice Exam

What type of bond is formed between sodium and chlorine to create NaCl?

1. Covalent bond

2. Metallic bond

3. Ionic bond

4. Hydrogen bond

The correct answer is: Ionic bond

The bond formed between sodium and chlorine to create sodium chloride (NaCl) is known as an ionic bond. This type of bond occurs when one atom donates an electron to another, leading to the formation of charged ions. In this case, sodium, which has one electron in its outer shell, readily loses that electron to achieve a stable electron configuration similar to that of noble gases. This loss of an electron transforms sodium into a positively charged ion (Na⁺). Chlorine, on the other hand, has seven electrons in its outer shell and requires one additional electron to complete its octet. When sodium transfers its electron to chlorine, it becomes negatively charged (Cl⁻). The opposite charges of these ions result in an electrostatic attraction that forms the ionic bond. This bond is characterized by its strength, leading to the formation of a crystalline lattice structure in the solid phase of NaCl, which has high melting and boiling points. In contrast, covalent bonds involve the sharing of electrons between atoms, which is not the case here. Metallic bonds involve a ‘sea of electrons’ shared among a lattice of metal atoms, which also does not apply. Hydrogen bonds are a specific type of weak attraction between a hydrogen atom covalently bonded