which group on the periodic table contains magnesium
Group 12 element Although group 12 lies in the d-block of the modern 18-column periodic table, the d electrons of zinc, cadmium, and (almost always) mercury behave as core electrons and do not take part in bonding. This behavior is similar to that of the main-group elements, but is in stark contrast to that of the neighboring group 11 elements (copper, silver, and gold), which also have filled d-subshells in their ground-state electron configuration but behave chemically as transition metals. For example, the bonding in chromium(II) sulfide (CrS) involves mainly the 3d electrons; that in iron(II) sulfide (FeS) involves both the 3d and 4s electrons; but that of zinc sulfide (ZnS) involves only the 4s electrons and the 3d electrons behave as core electrons. Indeed, useful comparison can be made between their properties and the first two members of group 2, beryllium and magnesium, and in earlier short-form periodic table layouts, this relationship is illustrated more clearly. For instance, zinc and cadmium are similar to beryllium and magnesium in their atomic radii, ionic radii, electronegativities, and also in the structure of their binary compounds and their ability to form complex ions with many nitrogen and oxygen ligands, such as complex hydrides and amines. However, beryllium and magnesium are small atoms, unlike the heavier alkaline earth metals and like the group 12 elements (which have a greater nuclear charge but the same number of valence electrons), and the periodic trends down group 2 from beryllium to radium (similar to that of the alkali metals) are not as smooth when going down from beryllium to mercury (which is more similar to that of the p-block main groups) due to the d-block and lanthanide contractions. It is also the d-block and lanthanide contractions that give mercury many of its distinctive properties.[28]