Answer:
c) Unit cell
Step-by-step explanation:
A unit cell is a basic repetitive structural unit that forms the building block of a crystalline solid's overall structure. Crystalline solids are characterized by their orderly and repeating arrangement of atoms, ions, or molecules in a three-dimensional pattern. This pattern is replicated throughout the entire crystal lattice.
A unit cell represents the smallest portion of a crystal lattice that, when stacked together, creates the entire crystal structure. It contains a specific arrangement of atoms, ions, or molecules that reflects the symmetry and repeating pattern of the crystal. The unit cell's arrangement determines the overall crystal's shape and properties.
In contrast:
- An "atom" is the smallest individual particle of an element, consisting of a nucleus of protons and neutrons, surrounded by electrons.
- A "molecule" is a group of atoms bonded together, forming the smallest unit of a compound that retains the compound's chemical properties.
- A "monomer" is a molecule that can join together with other monomers to form a polymer, which is a larger molecule made up of repeating units.
Among the options provided, "c) Unit cell" is the correct answer as the basic repetitive structural unit in a crystalline solid.