Why do magnets only attract iron, nickel and cobalt?

Ferromagnetic materials are what we refer to by the term "permanent magnet". Indeed, the strongest magnets are not made of either iron, cobalt or nickel, but from neodymium and other rare-earth metals. Its electron structure features 7 electrons with parallel spin within each atom. That's a huge number. read more

It depends on the permeability of the material. Permeability is the measure of the ability of a material to support the formation of a magnetic field within itself. read more

Dipole - a pair of equal and opposite electric charges or magnetic poles separated by a small distance. When these dipoles within any metal interact with electric or magnetic field, they align accordingly to the direction of respective field. read more