Why are heavy metals called heavy metals?

These metals are called heavy metals not because they are too heavy. But because they have large atomic no. And hence large atomic masses. These elements are mainly situated in the last 3 periods of the periodic table. And all of the f-block. read more

Arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and selenium are some of the metals (called 'heavy' because of their high relative atomic mass) which persist in nature and can cause damage or death in animals, humans, and plants even at very low concentrations (1 or 2 micrograms in some cases). read more