Question 10 of 20 Classify each compound as ionic or molecular: Ionic Molecular Answer Bank: CO2 KBr CH4 CuO
The Correct Answer and Explanation is:
Correct Answer:
Ionic
- KBr
- CuO
Molecular
- CO₂
- CH₄
Explanation
To classify a compound as ionic or molecular, we must examine the types of elements it contains and the nature of the chemical bond between them. The primary distinction is that ionic compounds typically form between a metal and a nonmetal, while molecular compounds form between two or more nonmetals.
Ionic Compounds:
An ionic bond is created by the transfer of electrons from a metal atom to a nonmetal atom. This transfer results in the formation of positively charged ions (cations) and negatively charged ions (anions). The strong electrostatic attraction between these oppositely charged ions holds the compound together.
- KBr (Potassium bromide): Potassium (K) is an alkali metal from Group 1 of the periodic table, and Bromine (Br) is a nonmetal halogen from Group 17. The combination of a metal and a nonmetal indicates an ionic bond. Potassium donates one electron to become a K⁺ ion, and bromine accepts that electron to become a Br⁻ ion.
- CuO (Copper(II) oxide): Copper (Cu) is a transition metal, and Oxygen (O) is a nonmetal. This metal-nonmetal pairing forms an ionic compound. Copper loses two electrons to form the Cu²⁺ cation, and oxygen gains two electrons to form the O²⁻ anion.
Molecular Compounds:
A molecular, or covalent, bond involves the sharing of electrons between nonmetal atoms. Instead of transferring electrons, the atoms share them to achieve a more stable electron configuration, forming distinct, neutral units called molecules.
- CO₂ (Carbon dioxide): Carbon (C) and Oxygen (O) are both nonmetals. When these two elements bond, they share electrons to form covalent bonds. This sharing results in the formation of individual CO₂ molecules, making it a molecular compound.
- CH₄ (Methane): Carbon (C) and Hydrogen (H) are both nonmetals. They share electrons to form covalent bonds, creating stable methane molecules. Therefore, methane is classified as a molecular compound.
