Solubility of the alkaline earth's metal sulphates in water decreases in the sequence

• Mg>Ca>Sr>Ba

• Ca>Sr>Ba>Mg>

• Sr>Ca>Mg>Ba

• Sr>Ca>Mg>Ba

212.

Which of the following pairs of ions are isoelectronic and isostructural? 

• 
• 
• 
• 

The number of d- electrons in Fe²⁺ (Z = 26) is not equal to the number of electrons in which one of the following?

• S- electronic in Mg (Z=12)

• p-electrons in Cl( Z=17)

• d- electrons in Fe (Z=26)

• d- electrons in Fe (Z=26)

which of the following orders of ionic radii is correctly represented?

• H^- > H >H⁺

• Na⁺ >F^- >O^2-

• F^- > O^2->Na⁺

• F^- > O^2->Na⁺

Be²⁺ is isoelectronic with which of the following ions?

• H⁺

• Li⁺

• Na⁺

• Na⁺

Identify the wrong statement in the following.

• Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius

• Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius

• Atomic radius of the elements increases as one moves down the first group of the periodic table

• Atomic radius of the elements increases as one moves down the first group of the periodic table

Which of the following represents the correct order of increasing electron gain enthalpy with negative sign for the elements O, S, F and Cl?

• Cl < F < O < S

• O < S < F< Cl

• F < S < O < Cl

• F < S < O < Cl

Which of the following pairs has the same size? 

• Fe²⁺ , Ni²⁺

• Zr⁴⁺, Ti⁴⁺

• Zr⁴⁺, Hf⁴⁺

• Zr⁴⁺, Hf⁴⁺

Which one of the following ion has electronic configuration [Ar] 3d⁶?
(At. no:  Mn = 25, Fe = 26, Co = 27, Ni = 28)

• Ni³⁺

• Mn

• Fe³⁺

• Fe³⁺

Among the elements Ca, Mg, P and Cl, the order of increasing atomic radii is 

• Mg< Ca < Cl < P

• Cl < P < Mg < Ca

• P < Cl < Ca < Mg

• P < Cl < Ca < Mg