The s-Block Elements

Arrange Na⁺, Mg⁺ and Al³⁺ in increasing order of energy of hydration.

• Na⁺ < Mg⁺ < Al³⁺

•  Al³⁺<  Mg⁺ < Na⁺

• Al³⁺ < Na⁺ < Mg²⁺

• Mg²⁺< Al³⁺ < Na⁺

Iron pipes, lying in acidic soil, are often attached to the blocks of magnesium for their protection from rusting, because magnesium

• is lighter than iron

• is readily converted into positive ion

• forms a corrosion-resistant alloy with iron

• prevents air from reaching the surface of iron

Which one of K, I, Cl and Li will display the highest first ionisation energy?

• K

• I

• Cl

• Li

You may have noticed that chicken-egg is very strong along its long axis so much so that it does not break even when pressed very hard. Which of the following is the main constituent of egg-shell?

• CaSO₄·2H₂O

• CaSO₄·1/2H₂O

• CaSiO₃

• CaCO₃

The number of sodium atoms in 2 moles of sodium ferrocyanide is

• 12 × 10²³

• 26 × 10²³

• 34 × 10²³

• 48 × 10²³

Nuclear attraction is often the deciding control factor for the association of neutral molecules to a given metal ion. Which one of the following represents the correct order of stability of the ions?

[Be(H₂O)₄]²⁺, [Mg(H₂O)₄]²⁺, [Ca(H₂O)₄]²⁺ and [Sr(H₂O)₄]²⁺ ?

• [Be(H₂O)₄]²⁺ > [Sr(H₂O)₄]²⁺> [Mg(H₂O)₄]²⁺ > [Ca(H₂O)₄]²⁺

• [Ca(H₂O)₄]²⁺> [Mg(H₂O)₄]²⁺ > Be(H₂O)₄]²⁺  > [Sr(H₂O)₄]²⁺

• [Sr(H₂O)₄]²⁺ > [Ca(H₂O)₄]²⁺> [Mg(H₂O)₄]²⁺ > Be(H₂O)₄]²⁺

• [Be(H₂O)₄]²⁺> [Mg(H₂O)₄]²⁺ >  [Ca(H₂O)₄]²⁺ > [Sr(H₂O)₄]²⁺

Which of the following represents correct acidity order Li₂O , BeO and B₂O₃ ?

• Li₂O < BeO < B₂O₃

• B₂O₃ < BeO < Li₂O

• BeO < Li₂O < B₂O₃

• BeO < B₂O₃ < Li₂O

Alkaline earth's metals are denser than alkali metals, because metallic bonding in alkaline earth's metal is

• stronger

• weaker

• volatile

• not present

The incorrect statements among the following is

• the first ionisation potential of Al is less than the first ionisation potential of Mg

• the second ionsiation potential of Mg is lower than the second ionsiation potential of Na

• the first ionisation potential of Na is less than the first ionisation potential of Mg

• the third ionisation potential of Mg is greater than the third ionisation potential of Al

The pairs of compounds which cannot exists together in a solution is

• NaHCO₃ and NaOH

• Na₂CO₃ and NaOH

• Na₂CO₃ and NaHCO₃

• NaHCO₃ and NaCl