In the series Sc `(Z=21)` to Zn `(Z=30)`, the enthalpy of atomisation of zinc is lowest, i.e. `126 "kJ mol"^(-1)` . Why ?

Why enthalpy of atomisation Zn is the lowest in the first transition series ?

Account of the following. (i) The enthalpy of atomisation is lowest for Zn in 3d -series of the transition elements. (ii) Identify the metal in MO_(3)F and justify your answer. (iii) Transition metals form a large number of complexes. (iv) d^(1) configuration is very unstable in ions.

(i) Write the balanced equations to represent what happens when (a) acidified potassium permanganates reacts with hydrogen sulphide ? (b) acidified potassium dichromate solution reacts with iron (II) solution (ionic equation) ? (ii) The figure given below illustrates the first ionisation enthalpies of first, second and third series of transition elements. (a) Which series amongst the first, second and third series of transition elements have the highest first ionisation enthalpy and Why ? (b) Why there is a fall in IE_(2) from Cr to Mn and from Cu to Zn ? Explain.

The activation energy of a first order reaction is 187.06" kJ mol"^(-1) at 750 K and the value of pre-exponential factor, A is 1.97 xx 10^(12)" s"^(-1) . Calculate the rate constant and half-life. (Given, e^(-30) = 9.35 xx 10^(-14) )

Assertion : If the species-area relationship are analysed among very large areas like the entire continents, the value of Z, i.e., slope of line in the range of 0.1 to 0.2. Reason : The value of Z, i.e., slope of line of species area relationship lies in the range of 0.6 to 1.2 when analysis is done among small areas.

The equiliberium constant for the reaction, 2X(g) + Y(g) ⇌ 2Z(g) is 2.25 litre mol^(-1) What would be the concentration of Y at equiliberium with 2.0 mole of X and 3.0 mole of Z in one litre vessel :

The temperature at which the reaction, Ag_2O(s)rarr2Ag(s)+I//2O_2(g) is at equilibrium is…….., Given triangleH =30.5 kJ mol^-1 and triangle S =0.066 kJ K^-1 mol^-1 :