Groups 1A and 2A: the alkali and alkaline Earth elements – Flashcards

Unlock all answers in this set

Unlock answers
question
base cations
answer
the alkali and alkaline earth metals, more specifically the cations Na+, K+, Mg2+, and Ca2+
question
the acidity or alkalinity of base cations
answer
they are actually acid neutral
question
why the cations Na+, K+, Mg2+, and Ca2+ are called base cations
answer
because they don't hydrolyze to produce protons in the pH 4-9 range of soil solutions
question
the oxidation state of the alkali metals (group 1A)
answer
+I
question
the valence of the alkali metals (group 1A)
answer
monovalent
question
which are stronger bases? group alkali metals or alkaline earth metals?
answer
alkali metals
question
the oxidation state of the alkaline earth metals (group 2A)
answer
+2
question
the valence of the alkaline earth metals (group 2A)
answer
divalent
question
why the alkali metals are considered strong bases
answer
because their pKa values are >? 14
question
why the alkaline earth metals are not considered strong bases
answer
because their pKa values range from 11.44 and 13.47exception: Be2+
question
the dominant species in the soil solution
answer
the divalent cations
question
when the divalent cation is the dominant species in the soil solution
answer
when the soil pH is less than approximately 11
question
where the alkali and alkaline earth metals are primarily found
answer
-aluminosilicate minerals
-carbonates
question
how alkali metals are released into the soil solution
answer
thru chemical weathering rxns
question
how alkali metals exist in soil solution
answer
they exist as free, uncomplexed, soluble monovatemt cations
question
do alkali metals form soluble complexes with inorganic or organic ligands?
answer
no
question
the only retention mechanism for alkali metal cations
answer
cation exchange
question
why cation exchange is the only retention mechanism for alkali metal cations
answer
because they do not form secondary mineral precipitates
question
one way some cations, such as K+, Cs+, and NH4+ can become unavailable
answer
fixation, in which they become trapped in a clay mineral, such as vermiculite, and become nonexchangeable
question
what makes Be2+ unique among the alkali earth metals?
answer
it forms neumerous hydrolysis products in pH > 5 solutions and has speciation similar to that of Al3+
question
do alkaline earth cations form stable aqueous complexes with inorganic ligands?
answer
yes
question
some things alkaline earth cations form stable aqueous complexes with in the soil solution
answer
-inorganic ligands
-soil organic matter
question
do alkali earth cations form precipitates in soil?
answer
they can, depending on geochemical conditions
question
the divalent cations that dominate the cation exchange phase of soils
answer
because they are generally the most abundant cations in soil sollutions
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New