How are zn, fe, cu alike and how are they different.? What trends do they follow on the periodic table How is their behavior consistent with their relative position in the periodic table.
Fe, Cu and Zn are transition elements of the fourth period. Their outermost electron shell contains one or may be two electrons in their s orbital (4s) but the remaining electron enters the last but one d sub shell, i.e., 3d. The elements of this block have the general characteristic properties which are intermediate between the elements of 2A and 3A groups. They are characterized by partially filled d subshells in the free elements and cations. The 4s and 3d subshells have similar energies, so small influences can produce electron configurations that do not conform to the general order in which the subshells are filled. Atomic radius decreases in a row from left to right. Ionization energies and electronegativities increase slowly across a row, as do densities and electrical and thermal conductivities, whereas enthalpies of hydration decrease. Anomalies can be explained by the increased stabilization of half-filled and filled subshells. Transition-metal cations are formed by the initial loss of 4s electrons, and many metals can form cations in several oxidation states. Higher oxidation states become progressively less stable across a row. Oxides of small, highly charged metal ions tend to be acidic, whereas oxides of metals with a low charge-to-radius ratio are basic. As example, atomic radius of these elements decreases in a row Fe>Cu>Zn and ionization energy increases in a row Zn<Cu<Fe.