Which of the following complex compounds will exhibit highest magnetic behaviour ?
`(At.No. Ti = 22, Cr = 24, Co = 27, Zn = 30)`

Options

A. `[Ti(en)_(2)(NH_(3))_(2)]^(4+)`
B. `[Cr(NH_(3))_(6)]^(3+)`
C. `[Zn(NH_(3))_(6)]^(2+)`
D. `[Sc(H_(2)O)_(3) (NH_(3))_(6)]^(2+)`

Answer

B

Explanation

A substance appears coloured because it absorbs light at specific wavelenghts in the visible part of the electromagnetic spectrum (400 to 700 nm) and transimts or reflects the rest of the wavelengths. Each wavelength og visible light represents a different colour. White light such as sunlight, is a combination of all colours, an object that absorbs all visible light appears black. All are octahedral ions. They are expected to absorb visible light provided they underage d-d transition, which is possible provided they undrage d-d transition, which is possibl providd metal ions have `d^(1)` - `d^(9)` electronic configurations. `Ti^(4+)` , `Sc^(3+)` `(d^(0))` `Zn^(2+)` `(d^(10))` species are colouress as they can't absorb visible light due to absence of d-d transition. On the other hand, `Cr^(3+)` `(3d^(6))` absorbs visible light as it can undergo d-d transition.