The most common oxidation state of an element is `-2`. The number of electrons present in the outermost shell is

Correct Answer - D Outermost electronic configuration of group 16 element is `ns^2` `np^4`.

Correct Answer - A Five vacant orbitals (3d-level) are present in Cl `(1s^2 2s^2 2p^6 3s^2 3p^5)` which belongs to 3rd period.

Correct Answer - B We know that, +3 oxidation is common in all series. Stable of +3 O.S. depends upon high hydration energy, high lactic energy and high I.P. `Nd^(2+)` -...

Correct Answer - A `[Co(NH_(3))_(5)CO_(3)]ClO_(4)` C.N. of Co = 6 , O.S. of `Co^(2+) is +3` It contain `Co^(3+)` as the centrl metal ion Co(Z = 27 ) : `[Ar^(18)]4s^(2)3d^(7)` `Co^(3+)...

Correct Answer - C Valency of A is 3 and that of X is (8-6), i.e.2

Correct Answer - C Configuration of `Cl^-` ion is `1s^2 2s^2 2p^6 3s^2 3p`

Correct Answer - A General configuration is `ns^(2)np^(2)`, hence there are two electrons of in p-level.

The complex is : `[CoCl_2(en)_2]`Cl. Complex is octahedral , CN of CO is 6 `Co^(3+)` has `3d^(6)` electronic configuration is +3

It is given that, `E_(K)=35.2keV,E_(L)=5.25keV,E_(M)=0.55 keV` `rArr" " E_(K)-E_(L)=(hc)/(lambda_(K_(A_(alpha))))=hv_(K_(alpha))` `rArr(35.2-5.25)xx10^(3)xx1.6xx10^(-19)=6.6xx10^(-34)v_(K_(alpha))` `rArr" " v_(K_(alpha))=(29.95xx10^(3)xx1.6xx10^(-19))/(6.6xx10^(-34))=7.2xx10^(-34)Hz` Similarly, `E_(K)-E_(M)=hv_(K_(beta))` `rArr" " v_(K_(beta))=((35.2-0.55)xx10^(3)xx1.63xx10^(-19))/(6.6xx10^(-34))=8.4xx10^(18)Hz` Also, `E_(L)-E_(M)=hv_(k_(alpha))` `rArr" " ((5.25-0.55)xx10^(3)xx1.6xx10^(-19))/(6.6xx10^(-34))=1.1xx10^(18)Hz`

Correct Answer - A `L=(nh)/(2pi)` it does not denpend on Z