Crystals

Question 1

Greek term * to denote both ice and quartz

Answer 1

Krystallos

Question 2

For a substance to be considered a crystal, it must be a * that forms * of ions or molecules that bond together. This pattern called * is repeated in the * throughout the structure of the entire crystal

Answer 2

homogeneous solid,
regular, repeated pattern
unit cell
same arrangement

Question 3

Materials that possess this internal organization, where unit cell is repeated in the same arrangement throughout the structure of the entire crystal are described as *
Example:

Answer 3

Crystalline solids

Minerals

Question 4

Have structures where the atoms or molecules are arranged randomly throughout the material
Example:

Answer 4

Non-crystalline solids

Glass

Question 5

The external form of the crystal is dependent on its

Answer 5

internal structure

Question 6

However, the formation of smooth plane surfaces, which define the * of the crystal, is dependent on the * prevalent during the crystallization

Answer 6

geometric shape

conditions

Question 7

Crystals may form from:

Factors:

Answer 7

solutions, melt, vapor

Temperature, pressure, concentrations

Question 8

Crystallization is defined by two stages:

Answer 8

Nucleation and growth

Question 9

Difference between nucleation and growth

Answer 9

Nucleation begins when ions or molecules become concentrated in a specific region
Growth continues as more ions or molecules become attracted and bond to the nucleation site until it precipitates out of the medium

Question 10

• begins when ions or molecules become concentrated in a specific region. When they reach what is known as *, the attraction between the ions or molecules becomes strong enough for them to bond together, forming a *.

Answer 10

Nucleation, critical size, protocrystal

Question 11

As this area of concentration increases, the protocrystal develops into a * to which more ions or molecules adhere themselves

Answer 11

nucleation site

Question 12

• continues as more ions or molecules become attracted and bond to the nucleation site until it precipitates out of the medium. At this point, more ions and molecules can stick to the surface of the growing size, until * can be achieved between the components still * in the medium and those * into the crystal

Answer 12

Growth
equilibrium
dispersed, locked

Question 13

In solution, the components of crystal are separated into individual units in the solvent by means of *. Thus, the ions and molecules fall naturally into their appropriate place in the * structure
Example

Answer 13

evaporation, repetitive

Formation of rock salt from sea water

Question 14

Crystals may also form from solutions by *

Answer 14

lowering temperatures or pressure

Question 15

Crystals form from melts similarly as from solutions, except that instead of solutes simply separating from solvents, melts involve a *
Example:

Answer 15

change of phase

Water (melted ice)

Question 16

Magmas contain a random distribution of ions of many elements. With a decrease in temperature, these various ions become attracted to one another, forming * of different *. As crystal growth proceeds, these nuclei enlarge to become the mineral grains of the resulting *

Answer 16

crystal nuclei, minerals

igneous rocks

Question 17

When the vapors are *, the ions or molecules dispersed in the vapor are brought in proximity to each other and allowed to bond, producing a *
Example

Answer 17

cooled, crystalline solid

Formation of snowflakes from air that is heavy with water vapor