Which of the following statements correctly describes a key difference between ionic and covalent compounds?

• A. Ionic compounds form between nonmetals only, while covalent compounds form between metals and nonmetals.
• B. Ionic compounds consist of positive and negative ions held together by electrostatic forces, while covalent compounds involve atoms sharing electrons.
• C. Covalent compounds conduct electricity in the solid state, while ionic compounds do not.
• D. Ionic compounds are always gases at room temperature, while covalent compounds are always solids.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the nature of ionic compounds. Ionic compounds are formed by the transfer of electrons from one atom to another, resulting in positive and negative ions. These ions are held together by strong electrostatic forces called ionic bonds.
2. Step 2: Understand the nature of covalent compounds. Covalent compounds are formed when atoms share electrons to achieve a full outer shell, creating covalent bonds. These bonds involve electron sharing rather than electron transfer.
3. Step 3: Analyze the given statements by comparing the fundamental bonding types. Ionic compounds consist of ions held by electrostatic attraction, while covalent compounds involve shared electrons between atoms.
4. Step 4: Evaluate the incorrect statements: Ionic compounds do not form only between nonmetals; they typically form between metals and nonmetals. Covalent compounds generally do not conduct electricity in the solid state, and ionic compounds are usually solids at room temperature, not gases.
5. Step 5: Conclude that the correct key difference is that ionic compounds consist of positive and negative ions held together by electrostatic forces, whereas covalent compounds involve atoms sharing electrons.