Question

31. Ti(H2O).P is a colored complex whereas (Ti(H20).]4+ is colourless. -Explain why? Give the
General electronic configuration of f-block elements.​

Answer 1

CORRECT QUESTION:

[ Ti(H₂O)₆ ]³⁺ is a coloured complex whereas [ Ti(H₂O)₆ ]⁴⁺ is colourless. Explain why? Give the general electronic configuration of f-block elements.

GIVEN:

• [ Ti(H₂O)₆ ]³⁺ is a coloured complex whereas [ Ti(H₂O)₆ ]⁴⁺ is colourless.

TO EXPLAIN:

• The colour property of Ti in [ Ti(H₂O)₆ ]³⁺ and [ Ti(H₂O)₆ ]⁴⁺.

EXPLANATION:

[ Ti(H₂O)₆ ]³⁺:

• Oxidation state of Ti is x + 0 = 3 → x = 3

Electronic Configuration of Ti⁺³ :

• Electronic Configuration of Ti is 4s² 3d².

• + 3 indicates removal of three electrons.

• Electronic Configuration of Ti⁺³ is 4s⁰ 3d¹.

$\setlength{\unitlength}{1 cm} \begin{picture}(0,0)\thicklines\put(2.6,0.6){ \boldsymbol {3d^1} }\put(0.05,0.6){ \boldsymbol {4s^0} }\multiput(0,0)(0.5,0){2}{\line(0,1){0.5}}\multiput(0,0)(0,0.5){2}{\line(1,0){0.5}}\multiput(1.5,0)(0.5,0){6}{\line(0,1){0.5}}\multiput(1.5,0)(0,0.5){2}{\line(1,0){2.5}}\put(1.6,0.1){ \boldsymbol{\upharpoonleft} }\end{picture}$

• Since Ti⁺³ possess one unpaired electron, it shows the colour property.

[ Ti(H₂O)₆ ]⁴⁺:

• Oxidation state of Ti is x + 0 = 4 → x = 4

Electronic Configuration of Ti⁺⁴ :

• Electronic Configuration of Ti is 4s² 3d².

• + 4 indicates removal of three electrons.

• Electronic Configuration of Ti⁺⁴ is 4s⁰ 3d⁰.

$\setlength{\unitlength}{1 cm} \begin{picture}(0,0)\thicklines\put(2.6,0.6){ \boldsymbol {3d^0} }\put(0.05,0.6){ \boldsymbol {4s^0} }\multiput(0,0)(0.5,0){2}{\line(0,1){0.5}}\multiput(0,0)(0,0.5){2}{\line(1,0){0.5}}\multiput(1.5,0)(0.5,0){6}{\line(0,1){0.5}}\multiput(1.5,0)(0,0.5){2}{\line(1,0){2.5}}\end{picture}$

• Since Ti⁺⁴ possess no unpaired electrons, it will not shows the colour property.

General electronic configuration of f-block is (n - 2) f¹⁻¹⁴ (n - 1) d⁰⁻² ns².