Chapter 17, Problem 1AC

A naturally occurring inorganic solid element or compound with a crystalline structure is a

a. mineral.

b. crystal.

c. rock.

d. stone.

To determine

From the following options, the naturally occurring, inorganic solid element or compound which has a crystalline structure is called:

mineral.

crystal.

rock.

stone.

Answer to Problem 1AC

Solution:

Option (a) is correct.

Explanation of Solution

Introduction:

Minerals are the part of solid materials of earth’s crust having known chemical composition and well-defined crystalline structure. The unique chemical composition and crystal structure gives it a set of physical property that is harnessed through engineering and technology to meet human needs.

Explanation:

Reason for correct option:

Minerals are obtained from the earth’s crust which is a thin layer of lighter elements on the surface. So, minerals are strictly naturally occurring.

Since the composition of minerals mostly includes any of the eight elements (Oxygen, Silicon, Aluminium, Iron, Calcium, Sodium, Potassium, Magnesium). So the product is inorganic in nature.

The atoms of a mineral are arranged in a regular and repeated pattern which is called crystal structure. The uniqueness of the crystal structure gives minerals special physical and chemical features.

Note that while discussing minerals ignore organic minerals which are some rare groups of minerals chemically containing hydrocarbons.

Also, petroleum being naturally occurring and obtained from earth’s crust should not be misunderstood as mineral as it is in liquid state and it is organic in composition. It is classified as hydrocarbon.

Hence, option (a) is correct.

Reason for incorrect option:

Option (b) is incorrect because crystals can be manufactured by the process of crystallization. Crystals may exist in either solid or frozen non-crystalline state.

Option (c) is incorrect because rocks are not elements or compounds but an aggregation of minerals and other materials. The minerals may be of same type or different types. Aggregation may include materials that don’t have crystal structure.

Option (d) is incorrect as there is no major difference between a rock and stone chemically. The stones are smaller in size compared to rock.

Conclusion:

All the solid materials of earth crust that have unique chemical composition and crystal structure and have some special physical and chemical features called minerals.