Question

Generally transition elements form coloured salts due to the presence of unpaired electrons which of the following compounds will be coloured in solid state?

• A. $Ag_{2}SO_{4}$
• B. $CuF_{2}$
• C. $ZnF_{2}$
• D. $Cu_{2}Cl_{2}$

Answer 1

Answer: (B)

$CuF_{2}$

Answer 2

$Ag_{2}SO_{4}\overset{\quad\quad}{\rightarrow}Ag^{+}(4d^{10}) - colourless$

$CuF_{2}\overset{\quad\quad}{\rightarrow}Cu^{2 +}(3d^{9}) - coloured$

$ZnF_{2}\overset{\quad\quad}{\rightarrow}Zn^{2 +}(3d^{10}) - colourless$

$Cu_{2}Cl_{2}\overset{\quad\quad}{\rightarrow}Cu^{+}(3d^{10})$ - colourless