Term
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Definition
| the alkali and alkaline earth metals, more specifically the cations Na+, K+, Mg2+, and Ca2+ |
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Term
| the acidity or alkalinity of base cations |
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Definition
| they are actually acid neutral |
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Term
| why the cations Na+, K+, Mg2+, and Ca2+ are called base cations |
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Definition
| because they don't hydrolyze to produce protons in the pH 4-9 range of soil solutions |
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Term
| the oxidation state of the alkali metals (group 1A) |
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Definition
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Term
| the valence of the alkali metals (group 1A) |
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Definition
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Term
| which are stronger bases? group alkali metals or alkaline earth metals? |
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Definition
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Term
| the oxidation state of the alkaline earth metals (group 2A) |
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Definition
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Term
| the valence of the alkaline earth metals (group 2A) |
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Definition
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Term
| why the alkali metals are considered strong bases |
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Definition
| because their pKa values are >≈ 14 |
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Term
| why the alkaline earth metals are not considered strong bases |
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Definition
| because their pKa values range from 11.44 and 13.47
exception: Be2+ |
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Term
| the dominant species in the soil solution |
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Definition
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Term
| when the divalent cation is the dominant species in the soil solution |
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Definition
| when the soil pH is less than approximately 11 |
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Term
| where the alkali and alkaline earth metals are primarily found |
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Definition
-aluminosilicate minerals
-carbonates |
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Term
| how alkali metals are released into the soil solution |
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Definition
| thru chemical weathering rxns |
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Term
| how alkali metals exist in soil solution |
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Definition
| they exist as free, uncomplexed, soluble monovatemt cations |
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Term
| do alkali metals form soluble complexes with inorganic or organic ligands? |
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Definition
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Term
| the only retention mechanism for alkali metal cations |
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Definition
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Term
| why cation exchange is the only retention mechanism for alkali metal cations |
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Definition
| because they do not form secondary mineral precipitates |
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Term
| one way some cations, such as K+, Cs+, and NH4+ can become unavailable |
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Definition
| fixation, in which they become trapped in a clay mineral, such as vermiculite, and become nonexchangeable |
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Term
| what makes Be2+ unique among the alkali earth metals? |
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Definition
| it forms neumerous hydrolysis products in pH > 5 solutions and has speciation similar to that of Al3+ |
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Term
| do alkaline earth cations form stable aqueous complexes with inorganic ligands? |
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Definition
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Term
| some things alkaline earth cations form stable aqueous complexes with in the soil solution |
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Definition
-inorganic ligands
-soil organic matter |
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Term
| do alkali earth cations form precipitates in soil? |
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Definition
| they can, depending on geochemical conditions |
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Term
| the divalent cations that dominate the cation exchange phase of soils |
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Definition
| because they are generally the most abundant cations in soil sollutions |
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