Question

calcite is mineral that is found in limestone and marble. a model of the extended structure of calcite is shown below. which statement best describes the structure of calcite?
a. it is formed by a single type of freely moving atoms
b. it is formed by a repeating pattern of different types of atoms.
c. it is formed by a repeating pattern of a single type of atom
d. it is formed by different types of freely moving atoms.

Explanation:

Calcite is a mineral (a crystalline solid). In a crystalline solid, atoms are arranged in a repeating (crystal lattice) pattern. The model shows different atoms (O, Ca, C, indicated by different colors), so it has a repeating pattern of different types of atoms. Options A and D are wrong because in a solid (like calcite), atoms are not freely moving (freely moving atoms are in gases/liquids more freely, or in metals with delocalized electrons but calcite is an ionic/covalent crystal). Option C is wrong as there are different atom types (O, Ca, C), not a single type.

Answer:

B. It is formed by a repeating pattern of different types of atoms.