Why are magnets magnetic?

Magnets can adsorb not only iron, but also cobalt and nickel. The composition of magnets is actually the same as that of ordinary metals. They are magnetic because the atoms are arranged neatly, which will not cause the energy of the north pole and the guiding pole to cancel each other out. His principle is that magnets will produce closed concentric magnetic lines to indirectly affect other substances "iron, cobalt and nickel".

Whether a substance exhibits magnetism in a magnetic field determines whether it is attracted by a magnet. And this kind of magnetism is macroscopic magnetism, and macroscopic magnetism is the sum of microscopic magnetism. Microscopic magnetism here refers to the magnetism of atoms.

The magnetism of an atom is based on a single electron, which is called lone pair in chemistry. Iron has five electrons, and trivalent ions have five single electrons, so it is more magnetic. Copper has no single electron, so it is not magnetic.

Just because an atom has only one electron and has microscopic magnetism does not mean that it must have macroscopic magnetism. Many materials, adjacent microscopic magnetic moments, are forced to arrange in opposite directions because of their chemical structure, so they will never be magnetic macroscopically, which is antiferromagnetic materials.

Why is it magnetic? The high-speed rotation of electrons around the nucleus is equivalent to forming a circular flow, which produces magnetism according to the left-handed law. Because the direction of atoms in a general crystal is freely arranged, their respective magnetic fields will cancel each other out. In materials such as magnets, the directions of magnetic lines of force are neat and consistent, thus showing magnetism.

Why do magnets attract iron? Because under the action of external magnetic field, every micro-magnetic field of iron itself will change along the direction of magnetic field lines, thus producing a magnetic field consistent with the direction of magnetic field lines outside the magnet. The process of metal absorption is a process in which the rotation direction of internal electrons is forcibly changed.

Why can't magnets absorb copper? It should be related to the arrangement of electron layers of different metals. It may be because the outer electrons of copper are very unstable and cannot maintain a stable magnetic field direction under the action of magnetic field lines, so they cannot be attracted. But it seems that if the energy is large enough, it can be sucked. If an electromagnet is strong enough, it seems to attract not only iron, but also many metals.