The atomic radii of the elements are almost same of which series
$Fe - Co - Ni$
$Na - K - Rb$
$F - Cl - Br$
$Li - Be - B$
While filling up of electrons in the atomic orbitals, the $4 s$ orbital is filled before the $3 d$ orbital but reverse happens during the ionisation of the atom. Explain why?
Which of the following may be colourless
Besides $Zn$ and $Cu$, german silver contains the metal
Zinc forms two important alloys, $(i)$ Brass and $ (ii) $ German silver. Metals present in them mainly are
Transition metal with low oxidation number will act as