Differences between neutron and proton distributions were investigated for \beta -stable nuclei and for chains of isotopes and isotones up to drip line nuclei. The relativistic mean field theory with the parameter set NL-3 was used in calculations. Dependence of neutron and proton radius and mean density on relative neutron excess I=(N-Z)/A was found. Different deformations of neutron and proton matter were noticed.

PACS numbers: 21.10.Gv