Advertisements
Advertisements
Question
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Ionisation enthalpies
Advertisements
Solution
- In every series, the first ionisation enthalpy generally increases gradually as we move from left to right, although some exceptions are observed in every series.
- In the same respective vertical column (group), the first ionisation enthalpy of some elements of the 4d series is higher, and that of some elements is lower as compared to the elements of the 3d series, although the first ionisation enthalpy of the 5d series is significantly higher as compared to the 3d and 4d series.
- The reason for this is the poor shielding effect of the 4f electrons in the 5d series (known as lanthanoid contraction), which increases the effective nuclear charge and binds the outermost electrons very tightly.
APPEARS IN
RELATED QUESTIONS
Account for the following:
Mn shows the highest oxidation state of +7 with oxygen but with fluorine, it shows oxidation state of +4.
Give reasons:
Transition metals show variable oxidation states.
How would you account for the following : Transition metals form coloured compounds
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
Complete and balance the following chemical equations
`Fe^(2+) + MnO_4^(-) + H^+ ->`
Give reasons Iron has the higher enthalpy of atomization than that of copper.
The transition metals show _________ character because of the presence of unpaired· electrons and Cu+ is ____________ because of its electronic configuration is [Ar]3d10
The paramagnetic character in the 3d-transition series elements increases up to Mn and then decreases.
Transition metals with highest melting point is ____________.
Which is the most stable oxidation state of iron?
Why is \[\ce{HCl}\] not used to make the medium acidic in oxidation reactions of \[\ce{KMnO4}\] in acidic medium?
Explain why does colour of KMnO4 disappear when oxalic acid is added to its solution in acidic medium.
Identify A to E and also explain the reactions involved.
A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese are formed. Compound (C) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C) with conc. \[\ce{H2SO4}\] and \[\ce{NaCl}\], chlorine gas is liberated and a compound (D) of manganese along with other products is formed. Identify compounds A to D and also explain the reactions involved.
The element with atomic number 46 belongs to
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other in:-
In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).
[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]
