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Introduction          Three series of elements are formed by filling the 3d, 4d and 5d - subshells of electrons. Together these comprise the d - block elements. They are often called ‘transition elements’ because their position in the periodic table is between the s - block and p - block elements . Their properties are transitional between the highly reactive metallic elements of the s - block, which typically forms ionic compounds and the elements of the p - block, which are largely covalent. In the s and p - blocks, electrons are added to the outer shell of the atom. In the d - block, electrons are added to the penultimate shell, expanding it from 8 to 18 electrons. Typically the transition elements have an incompletely filled d - level. Group 12 (the zinc group) has a d 10 configuration and since the d - subshell is complete, compounds of these elements are not typical and show some differences from the others. The trans...