Zinc, cadmium and mercury, which are situated in group 12 of the periodic table, are silvery-white metals with low melting and boiling points. Mercury, indeed, with a melting point of -38.84 degrees Celsius, is the only metal to be liquid at room temperature.
Zinc and cadmium are rapidly tarnished in moist air, and all three elements react with many of the non-metals on heating. Mercury is more resistant to acidic attack, but although it does not react with dilute acids, it does dissolve in concentrated nitric acid and hot concentrated sulphuric acid. Both cadmium and mercury are resistant to alkalis.
The toxicity of the elements increases as we descend the group. Both cadmium and mercury are highly poisonous.
