If you place the iron near a magnet, the iron will be attracted to the magnet. Rust is made up of molecules that contain iron atoms and oxygen atoms. Rust is not attracted to the magnet. If rust contains iron atoms and iron is attracted to a magnet, why is rust not attracted to a magnet?
Depends on the amount of rust. We all know that before a magnet can attract iron, it must be placed close enough for the attraction to occur.
When iron begins to rust, molecules of oxygen and water are introduced between the iron molecules, causing them to separate. This decreases the magnetic field between the iron molecules. So slightly rusty iron will have weak magnetic properties because the separation is not so great. But very rusty iron will not have magnetic properties because the separation is greater.