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Published on: 29/08/2019
The d- and f- Block Elements
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Questions + Answers key
Take MCQ Chemistry Test
1.
The d-electron configuration of Mn2+ and Ti2+ is d5 and d2 respectively. Which one of these ions will be more paramagnetic?
2.
What is the highest oxidation state shown by Cr (Z=24)?
3.
Write the highest oxidation state shown by element with atomic number 23.
4.
Out of Cr2+ and Cr3+, which one is stable in aqueous solution?
5.
Write the outer electronic configuration of Cr atom (Z=24).
6.
There is hardly any increase in atomic size with increasing atomic numbers in a series of transition metals. Give reason.
7.
Among landthanoids, Ln(III) compounds are predominant. however, occasionally in solutions or in solid compounds, +2 and +4 ions are also obtained. Give reason.
8.
Most of the transition metal ions exhibit characterisitic in colours in aqueous solutions. Give reason.
9.
Lanthanoids form primarily +3 ions, while the actinoids usually have higher oxidation states in their compounds, +4 or even +6 being typical. Give reason.
10.
Why are Cr2+ reducing and Mn3+ oxidising when both have d4 configuration?
11.
Which element does not show variable oxidation state ?
Sc
V
Fe
Hg
12.
Irregular trend in the standard reduction potential value of the first row transition elements is due to
regular variation of first and second row enthalpies
irregular variation of sublimation ethalpies
regular variation of sublimation ethalpies
increase in number of unpaired electrons
13.
In first transition series which of the following has lowest enthalpy of atomisation ?
Sc
Cu
Yi
Zn
14.
Which of the following is not a transition element ?
Zn
Ru
Ag
Pb
15.
General electronic configuration of d - block elements is
(n - 1) d1-10ns1-2
ns2np1-6
(n - 2) f0-14(n - 1)1-2ns2
(n-1) d1-5ns1-2
16.
TiCI4 + A1(CH3)3
17.
Finely divided iron
18.
V2O5
19.
Cu2CI2
20.
Ni in the presence of hydrogen
1.
Mn2+ is more paramagnetic than Ti2+ because t has 5 unpaired electrons whereas Ti2+ has 2 unpaired electrons.
2.
The highest oxidation state shown by Cr is +6.
3.
Highest oxidation state shown by an element with atomic no.23 is +5.
4.
Highest oxidation state shown by an element with atomic no.23 is +5.
5.
Cr(24): [Ar] 3d5 4s1
6.
It is because effective nuclear charge does not increase appreciably as pairing of electrons in d-orbitals take place which cause repulsion after Mn(25).
7.
It is because effective nuclear charge does not increase appreciably as pairing of electrons in d-orbitals take place which cause repulsion after Mn(25).
8.
It is due to presence of unpaired electrons, they undergo d-d transition by absorbing visible light and radiate complementary colour.
9.
In Actinoids 5f, 6d and 7s orbitals have comparable energies and electrons from these orbitals can take part to show higher oxidation states.
10.
Cr2+ is reducing as its configuration changes from d4 to d3, the latter having a half-filled t2g level. On the other hand, the change from Mn3+ to Mn2+ results in the half-filled (d5) configuration which has extra stability.
11.
(a)
Sc
12.
(b)
irregular variation of sublimation ethalpies
13.
(d)
Zn
14.
(d)
Pb
15.
(a)
(n - 1) d1-10ns1-2
16.
( )
Ziegler-Natta catalyst
17.
( )
Haber's Process
18.
( )
Contact process
19.
( )
Sandmeyer reaction
20.
( )
Vegetable oil to ghee
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