<P> 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 . </P>
<P> 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 . </P>
which group on the periodic table contains magnesium
which group on the periodic table contains magnesium
group 2
group 2