Which term best describes sodium chloride?
a. element
b. compound
c. allotrope
d. homogeneous mixture
The correct answer and explanation is :
The correct answer is:
b. compound
Explanation:
Sodium chloride (NaCl), commonly known as table salt, is best classified as a compound because it consists of two different elements—sodium (Na) and chlorine (Cl)—that are chemically bonded together in a fixed ratio.
A compound is a pure substance formed when two or more elements are chemically combined in definite proportions. In the case of sodium chloride, sodium (a highly reactive metal) donates an electron to chlorine (a non-metal), forming an ionic bond. This transfer of electrons results in the formation of positively charged sodium ions (Na⁺) and negatively charged chloride ions (Cl⁻), which are held together by electrostatic forces in a crystal lattice structure.
Why Other Options Are Incorrect:
- a. Element: Elements consist of only one type of atom. Since sodium chloride contains both sodium and chlorine, it is not an element.
- c. Allotrope: Allotropes are different structural forms of the same element, such as diamond and graphite (which are both forms of carbon). Sodium chloride is a compound, not an allotrope.
- d. Homogeneous mixture: While sodium chloride dissolves in water to form a homogeneous solution, the salt itself is a pure substance, not a mixture. A homogeneous mixture, such as air or saltwater, contains multiple substances physically blended, whereas sodium chloride is chemically bonded.
Thus, sodium chloride is best classified as a compound because it consists of sodium and chlorine atoms chemically combined in a fixed ratio.
Here is an image representing the 3D molecular structure of sodium chloride (NaCl), showing the crystal lattice arrangement of sodium and chlorine ions.