Question 45

Pure crystals of the metallic element copper are composed of atoms.

Copper exists in a crystalline structure that is made up of closely packed atoms. In its pure metallic form, copper does not exist as molecules or ions but rather as a collection of individual atoms arranged in a specific geometric pattern.

A) Molecules

Molecules are formed from two or more atoms bonded together, typically in covalent compounds. Since copper is a metallic element and does not form discrete molecules in its pure form, this option is incorrect.

B) Compounds

Compounds consist of two or more different elements chemically bonded together in fixed proportions. Copper, in its pure state, is not a compound; it is a single element, making this choice inaccurate.

C) Ions

Ions are charged particles that result from the loss or gain of electrons by atoms. While copper can exist in ionic forms in various compounds (such as copper sulfate), pure copper crystals do not consist of ions; therefore, this option is incorrect.

D) Atoms

The correct answer, atoms, accurately represents the structural units of pure copper crystals. In metallic copper, the atoms are arranged in a regular lattice structure, contributing to its metallic properties.

Conclusion

The composition of pure copper crystals is fundamentally based on the arrangement of atoms, which distinguishes it from molecules, compounds, and ions. Other options fail to describe the nature of metallic copper accurately, reinforcing that the atomic structure is essential for understanding its properties and behavior as a pure element.