Along the period `(rarr)` atomic`//`ionic radii and metallic character decreases while `IE`, `EN` , non-metallic character and oxidising power increases. Down the group `(darr)`, atomic`//`ionic radii, metallic character and reducing character increase while `IE` and `EN` decrease. However, `Delta_(eg)H^(ɵ)` becomes less negative down a group but more negative along a period.
Correct order of `IE_(2)` of the following is

Options

A. `IE` and `EA` are defined at absolute zero temperature. At any other temperature, heat capacities for the reactants and product have to be taken into account.
B. The ionisation enthalpy `(Delta_(r)H^(ɵ))` and `IE` related to each other by the equation.
`Delta_(i)H^(ɵ)` (ionisation enthalpy ) `= [IE ("ionisation energy"+(5)/(2)RT]`
C. The electron gain enthalpy `(Delta_(eg)H^(ɵ))` and `EA` are related to each other by the equation:
`Delta_(eg)H^(ɵ)` (ionisation enthalpy ) `= [-IE ("electron affinity"-(5)/(2)RT]`
D. The valuye of `C_(p)` (heat capacity at constant pressure and `C_(v)` (heat capacity at constant volume) are `(3)/(2)R` and `(5)/(2)R` respectively)

Answer

A, B, C

Explanation

d. `C_(p) = (5)/(2) R` and `C_(v) = (3)/(2)R`.