Over the course of soil development from parent rock to high…

Over the course of soil development from parent rock to highly weathered soils, mineral weathering reactions occur that alter the surface chemistry of the soil.  Consider the weathering transformation sequence: muscovite/biotite → illite → vermiculite → smectite → kaolinite → gibbsite During the above weathering sequence, what general changes would be expected in following mineral chemical characteristics? Why? (a)  Permanent (structural) charge (b)  pH dependent (variable) charge (c)  Types of surface functional groups (d)  Cation exchange capacity (e)  Anion exchange capacity