The atomic radii from $Cr$ to $Cu$ is almost identical because of
Increasing nuclear charge from $Cr$ to $Cu$
Repulsion among increased electrons
Increased screening effect to nullify increased nuclear charge
All the above
Invar, an alloy of $ Fe$ and $ Ni $ is used in watches and meter scale, its characteristic property is
Which of the following has lowest percentage of carbon
Passing $H_2S$ gas into a mixture of $Mn^{+2}, Ni^{+2}, Cu^{+2}$ and $Hg^{2+}$ ions in an acidified aqueous solution precipitates
The number of unpaired electrons in $M{n^{ + 3}}$ is
In which of the following pairs are both the ions coloured in aqueous solution ?
(At. no. : $Sc = 21, Ti = 22, Ni = 28,$$ Cu = 29, Co = 27$)