$A$ copper coin was electroplated with $Zn$ and then heated at high temperature until there is a change in colour. What will be the resulting colour?

Which one of the following does not correctly represent the correct order of the property indicated against it?

The electronic configuration of chromium is

Properties common to the elements manganese,iron,cobalt,nickel,and copper include the ready formation by them all of:
$I$. Coloured ions in aqueous solution
$II$. Oxides of nitrogen are formed on reaction with concentrated $HNO_3$
$III$. Chlorides of formula $MCl_2$ and $MCl_3$

How many of the following lanthanide elements exhibit $+4$ oxidation state?
$Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy$

Identify the outer electronic configuration of the $first$ element of the $first$ transition series.