Test: The s-Block Elements - 1 (Old NCERT) - JEE MCQ

Na and K have ns¹ configuration so they are alkali metal.

Here KO2 is in superoxide form hence O.S. of O is -1/2 for each oxygen atom. Hence 2*1/2= 1, therefore k has +1 O.S.

Potassium ions are the most abundant cations. They participate in the oxidation of glucose to produce ATP

BaCO₃ is very stable due to size compatability factor . A larger cation can stablises a larger anion.

All of these statements are coorect as these halides absorb water and due to decrease in the hydration energy down the group tendency to from hydrates decreases.

Fr is radioactive.

M is alkali metal.

Alkaline Earth Metals loses 2 electron to attain noble gas configuration.

1^st element of 1^st group and the second element of 2^nd group exist in diagonal relationship.

Hence C is the correct answer.

The correct answer is Option B
Be is not readily attacked by acids due to formation of oxide layer.
The surface of beryllium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. It does not oxidize in air even at 600^oC. 
2Be+O₂⟶2BeO

While moving from left to right in periodic table basic character of oxide of elements will decrease. ∴→Increasing basic strength Al₂O₃<MgO<Na₂O    and while descending in the group basic character of corresponding oxides increases.  ∴→Increasing basic strength Na₂O<K₂O   ∴ Correct Order is Al₂O₃ < MgO <Na₂O <K₂O

Li due its small size have high Lattice energy value which compensates its high ionization energy so has most negative E⁰ value

The low ionisation enthalpies of the alkaline earth metals is because of their strong tendency to lose electrons due to their smaller nuclear charge and comparatively larger atomic size which results in weaker forces of attraction between the valence electrons and the nucleus.

Due to small size of Mg. Mg-O become more stronger hence tendency of OH to leave decreases thus basic character decreases.

Na₂CO₃ is used in textile industry.

Na and K ions help in transmission of nerve impulses.

The color of solution is due to the presence of ammoniated electron.

Correct Answer : a

Explanation : Atomic no. of Be, Mg, Ca, Sr, Ba are 4, 12,20,38,56 respectively.

On moving down the group, the effective nuclear charge on the outermost electrons decreases. Hence Ba can readily lose electrons and will be the most electropositive element among the alkaline earth metals.

BeCl₂ is soluble in ethanol. Except for beryllium halides, all other halides of alkaline earth metals are ionic in nature. Beryllium halides are essentially covalent and soluble in organic solvents.

BeSO₄ being unstable is readily soluble in water. Aslo hydration energy of Be is high due to small size.

Mg²⁺ and Ca²⁺ maintains the ion balance.

When the solution become diamagnetic color changes to bronze.

Ra salts are used in the treatment of Cancer.

LiF has very high lattice energy which cannot be compensated by Hydration Energy.

Exceptionally small size of Li is responsible for its anamolous behavior.