Why some ions like Zn^+2 Cu^+1 Sc^+3 Ti^+4 are colourless?

Open in App

Solution

Most of the transition metal compounds (ionic as well as covalent ) are coloured both in the solid as well as in aqueous solution. The colour is due to the presence of incomplete d-subshell. The electrons in d- subshell undergo d-d transition and thus impart colour to the compound.Thus for the compound to be coloured an essential requirement is incompletely filled d- subshell.

In case of Sc3+ , Ti4+ and Zn2+ if we see the electronic configuration ,

Sc3+ (Z=21) : 1s22s22p63s23p64s23d0 ( Z = atomic number )
Ti4+ (Z=22) : 1s22s22p63s23p64s23d0
Zn2+ (Z=30) : 1s22s22p63s23p64s23d10

Thus Sc3+ and Ti4+ have completely empty d-orbitals and there are no electrons for the d-d transition thus they are colourless.

Zn2+ has completely filled d-orbitals and there are no vacant d-orbitals for the transition of electrons , hence it is also colourless

Suggest Corrections

Similar questions

C u^{2 +}

Z n^{2 +}

{Z n}^{+ +}

Z n

C u^{+ 2}

Z n^{+ 2}

Which of the following are TRUE for $Z n S$ type and $C a F_{2}$ type structure?

Join BYJU'S Learning Program