Give reason: (i) Transition elements exhibit higher enthalpies of… - Vidyadip

Question

Give reason:
(i) Transition elements exhibit higher enthalpies of atomisation.
(ii) In aqueous solution, $Cr ^{2+}$ is stronger reducting agent than $Fe ^{2+}$.
(iii) The second ionisation enthalpy of Cu is higher then $Z n$.

✓

Answer

→ (i) Because transition elements have more unpaired electrons, they have stronger interatomic interactions and hence stronger bonding. so....
→ (ii) In $Cr ^{2+}$ to $Cr ^{3+} d ^4 \rightarrow d ^3$ occurs and in $Fe ^{2+}$ to $Fe ^{3+} d ^6 \rightarrow d ^5$ occurs. In aq. medium $d ^3$ is more stable than $d^5$.
→ (iii) In 2nd ionisation enthalpy of $Cu e ^{-}$is removed from $3 d^{10}$ and in Zn from $4 s^1 .3 d^{10}$ is more stable configuration than $4 s^1$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from The d-and f-Block Elements→The d-and f-Block Elements — all question types→Chemistry STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

For the first order thermal decomposition reaction, the following data were obtained:
$\text{C}_{2}\text{H}_{5}\text{Cl}\text{(g)}\rightarrow \text{C}_{2}\text{H}_{4}\text{(g)} + \text{HCl}\text{(g)} $

Time/sec	Total pressure/atm
0	0.30
300	0.50

Calculate the rate constant
(Given: log 2 = 0.301, log 3=0.4771, log 4 =0.6021)

Using valence bond theory predict the geometry and magnetic behaviour of [Cr(NH₃)₆]³⁺ion[Cr=24].
Write IUPAC name of:

[Pt(NH₃)₂Cl₂].

An organic compound ‘A’ (C₃H₄) on hydration in presence of H₂SO₄/ HgSO₄ gives compound ‘B’ (C₃H₆O). Compound ‘B’ gives white crystalline product (D) with sodium hydrogensulphite. It gives negative Tollens’ test and positive iodoform’s test. On drastic oxidation ‘B’ gives compound ‘C’ (C₂H₄O₂) along with formic acid. Identify compounds ‘A’, ‘B’ and ‘C’ and explain all the reactions.

Why the soaps do not work in hard water?

Account for the following :
(i) The order of reactivity of halogen acids towards alcohols is : $\quad HI > HBr > HCl$
(ii) The order of acidity of alcohols falls in the order : primary > secondary > tertiary.
(iii) The - OH group in phenols is ortho- and para-directing.

Give the function of steroid hormones.

Describe the trends in the following properties of the first series of the transition elements:

Oxidation states.
Atomic sizes.
Magnetic behaviour of dipositive gaseous ions (M²⁺).

Write all the possible isomers of [Co(NH₃)₅(SCN)]Cl.

Explain mechanism of nucleophilic addition reaction of aldehydes and ketones with figure.

Give the structures and IUPAC names of the products expected from the following reactions:
a. Catalytic reduction of butanol.
b. Hydration of propene in the presence of dilute sulphuric acid.
c. Reaction of propanone with methyl magnesium bromide followed by hydrolysis.