D&F block elements

Which of these has highest 3rd ionisation enthalpy?

• Sc

• Fe

• Mn

• Cr

Answer explanation

Mn+2 and Zn +2 have a stable d5/d10 configuration and thus its third IE will be high. IE2 of Cr & Cu will be high

Which transition element does not show variable oxidation state?

Answer explanation

Sc shows only +3 and Zn shows only +2 due to stability of noble gas configuration/d10 respectively.

In D-block, on going down the group stability of higher oxidation state___

• Increases

• Decreases

• Stays same

Answer explanation

Unlike P-Block elements

Cr⁺² is a ___ agent

• Reducing

• Oxidising

Answer explanation

Cr's d orbital split into two parts and its 4e occupy orbitals in such way. Now, in order to make Cr+2 stable, instead of gaining electron it loses one to make its t₂g half filled. Unlike Mn which does not split so just gains one electron to make d5

Max OS of Mn with halogen is-

• +7

• +5

• +4

• +6

Answer explanation

MnF₄

Which of these iodides does not exist?

• FeI₂

• CoI₃

• MnI₄

• CrI₆

• Cu₂I2

Which of the followng oxides are amphoteric in nature-

• V₂O₅

• Cr₂O₃

• TiO₂

• Mn₂O₇

• MnO₂

Answer explanation

V₂O_{5 and TiO2 can also be considered acidic}

Which of these is acidic oxide-

• CrO₃

• CrO₅

• Mn₂O₇

• MnO3

• FeO

Answer explanation

FeO, CuO, NiO, Mn2O3, Sc2O3, TiO are basic

Ferrates (VI) (FeO₄)^2- reasily decompose to

• Fe₂O₃

• O₂

• FeO

• Fe

The ability of oxygen to stabilise high oxidation states exceeds that of fluorine

• True 

• False

Answer explanation

Max OS of Mn with F: MnF4

with O: Mn2O7