Tag: the s-block elements (alkali and alkaline earth metals)

Questions Related to the s-block elements (alkali and alkaline earth metals)

The metal ions (charged particles) that are required for contraction of muscles in human beings and animals are ions of:

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

  1. calcium

  2. sodium

  3. potassium

  4. iron

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Correct Option: A
Explanation:

$Ca^{2+}$ ions are required for contraction of muscles in humans.

Which of the following metals is required as a cofactor by all enzymes utilizing ATP in phosphate transfer?

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

  1. K

  2. Ca

  3. Na

  4. Mg

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Correct Option: D
Explanation:

Mg binds to phosphate group in ATP thus making a complex that catalyses phosphate transfer. 

The main constituents of pearl are:

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

  1. ammonium sulphate and sodium carbonate

  2. aragonite are conchiolin

  3. calcium carbonate and magnesium carbonate

  4. calcium oxide and ammonium chloride

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Correct Option: B
Explanation:

The chief component of the nacre that constitutes the pearl is aragonite $(CaCO _3)$. Nacre also contains a small amount of conchiolin, a hornlike organic substance (albuminoid) that is the main constituent of the mollusk's outer shell.

Which of the following statements is/are false?

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

  1. The halides of beryllium are electron deficient and are polymeric with halogen bridges.

  2. $BeF _2$ is very soluble in water owing to high solvation energy of Be but fluorides of other alkaline earth metals are almost insoluble.

  3. CaO, SrO and BaO react exothermically with water forming soluble hydroxides.

  4. The bicarbonates of alkaline earth metals are only stable in solutions.

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Correct Option: A,B,C,D

Select correct statement(s).

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements biological importance of sodium and potassium

  1. $Mg^{2+}$ ions are necessary for the activation of phosphate transfer enzymes.

  2. Mg is present in chlorophyll of green plants.

  3. Mg is present in chlorophyll used in photosynthesis in green plants.

  4. All the above are correct statements

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Correct Option: D

Chlorophyll, the green component of plants contains:

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements

  1. $Ca^{2+}$

  2. $Be^{2+}$

  3. $Mg^{2+}$

  4. $Ba^{2+}$

Show answer
Correct Option: C
Explanation:

In plants, $Mg^{2+}$ is present in chlorophyll which is a green pigment useful for photosynthesis. It absorbs sunlight.

Bones and teeth contain:

chemistry the s-block elements (alkali and alkaline earth metals) biological importance of magnesium and calcium biological importance of elements biological importance of s block elements

  1. Calcium dihydrogen phosphate

  2. Apatite

  3. Calcium phosphide

  4. None of the above

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Correct Option: B
Explanation:

Bones and teeth contains Apatite which is a group of phosphate minerals and contains calcium. Its formula can be represented as $Ca _5(PO _4) _3(F,Cl,OH)$.

Which of the following is organometalic compound 

chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

  1. Methyl lithium

  2. Lithium methoxide

  3. Lithium dimethyl amide

  4. Lithium acetate

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Correct Option: A
Explanation:

$LiCH _3$ have metal carbon bond so considered organometic compound and other do not have. 

Which of the following compounds on thermal decomposition yields a basic as well as an acidic oxide?

chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

  1. $KClO _3$

  2. $NaNO _3$

  3. $K _2CO _3$

  4. $MgCO _3$

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Correct Option: D
Explanation:

$MgCO _3\xrightarrow{\Delta} MgO+CO _2$

Since oxides of metals are basic in nature, $MgO$ is basic, and $CO _2$ is acidic. Hence decoposition of $MgCO _3$ yields both acidic and basic oxides

Which nitrate will decompose to give $NO _2$ on heating?

chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

  1. $NaNO _3$

  2. $KNO _3$

  3. $4RbNO _3$

  4. $LiNO _3$

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Correct Option: D
Explanation:

Only $LiNO _3$ gives $NO _2$ on heating. All other nitrates give oxygen.
$4LiNO _3 \, \xrightarrow{\Delta} \, 2Li _2O \, + \, 4NO _2 \, + \, O _2.$
$2NaNO _3 \, \xrightarrow{\Delta} \, 2NaNO _2  \, + \, O _2$