Zinc and mercury do not show variable valency like d-block elements because

• they are soft

• their d- shells are complete

• they have only two electron in the outer most sub shell

• Their d- shell are completed

Mark the oxide which is amphoteric in character

• CO₂

• SiO₂

• SnO₂

• CaO

The transition metals mostly are

• diamagnetic

• paramagnetic

• neither diamagnetic nor paramagnetic

• both diamagnetic and paramagnetic

The formula of a phosphate of a metal M, is MPO₄. The formula of its nitrate will be

• MNO₃

• M(NO${}_3^{-}$)₂

• M(NO₃)₃

• M₂(NO₃)₃

115.

The d-block elements consists mostly of

• mono-valent metals

• all non-metals

• elements which generally form stoichiometric metal oxide

• many metals with catalytic properties

Which one of the following is an example of non-typical transition elements?

• Li, K, Na

• Be, Al, Pb

• Zn, Cd, Hg

• Ba, Ca, Sr

Which ion is colourless?

• Cr⁴⁺

• Sc³⁺

• Ti³⁺

• V⁴⁺

Which of the following statement is not correct?

• La(OH)₃ is less basic than Lu(OH)₃.

• In lanthanide series ionic radius of Lu³⁺ ion decreases.

• La is actually an element of transition series rather lanthanide.

• Atomic radius of Zr and Hf are same because of lanthanide contraction.

E°= -0.44V for the reaction, Fe²⁺ + 2e^- → Fe and E°= -0.76 V for the reaction, Zn²⁺ + 2e^- → Zn. Which of the following statement is correct?

• Fe is more electropositive

• Zn is more electropositive

• Zn is more electronegative

• None of the above

Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionisation enthalpy? 

• Vanadium (Z = 23)

• Manganese (Z = 25)

• Chromium (Z= 24)

• Iron (Z = 26)