$word_{count}$: 200

Magnetic behaviour depends on electron configuration. Diamagnetic: all electrons paired, weak repulsion by magnetic field (Cu, Ag, NaCl, benzene, H2O). chi < 0. Paramagnetic: unpaired electrons present, weak attraction, magnetism lost when field removed (O2, NO, $Cu^{2+}$, $Fe^{3+}$, $Cr^{3+}$). chi > 0 but small. Ferromagnetic: spontaneous alignment of electron spins in domains, strong attraction, permanent magnetism possible (Fe, Co, Ni, CrO2, Gd). Curie temperature: above this, becomes paramagnetic (Fe: 1043 K). Antiferromagnetic: adjacent spins antiparallel, zero net moment (MnO, MnO2, Cr2O3). Neel temperature: above this, becomes paramagnetic. Ferrimagnetic: antiparallel but unequal moments, net magnetic moment (Fe3O4, MgFe2O4). Above Curie temperature, becomes paramagnetic. For JEE: know definitions, examples, and how to predict based on electron configuration.