Soils containing smectite clay minerals have a high potential for swelling and shrinking because
A) the relatively large, plate-shaped clay crystals pack together tightly.
B) the very small clay crystals have a large surface area to attract water molecules.
C) the clay-rich soils allow water to percolate through easily.
D) organic matter in the soils retains water during dry periods.
E) the soil particles break apart easily during freeze-thaw cycles.

Question

Quizplus · Accepted Answer

Smectite clay minerals have a high cation exchange capacity due to their large surface area, and they attract water molecules through hydrogen bonding. This leads to the expansion of the clay minerals and an increase in soil volume during wet periods, and the opposite during dry periods, resulting in swelling and shrinking.

Soils Containing Smectite Clay Minerals Have a High Potential for Swelling