Periodicity
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I am doing an assignment on the trends in the periodic table. I am trying to find any anomalies/irregularities, particularly in Groups I and IV and accross Period 3.
210208
Corrie writes .......
This is a very wide ranging question and really you should be doing the research on the properties of the elements yourself. Here are a few pointers to areas that may be worth looking at more closely.
Group 1: the trends in physical and chemical properties are pretty regular, except for lithium, whose small atomic and ionic radius causes it to behave more like magnesium in Group 2 at times.
This is the so-called 'diagonal relationship', for example lithium forms only one oxide (Li2O), its carbonate can be decomposed on heating and is insoluble in water, and it combines directly with nitrogen or carbon.
Group IV: here the trends undergo a much more dramatic change - not so much anomalies as a complete change from non-metallic character at the top (C) to metallic character (Sn, Pb) at the bottom of the group. Si & Ge find themselves in the middle of this change, so could be considered as having 'anomalous' properties: conductivity, oxidation states, acidic or basic oxides, etc
Period 3: the regular trend across the period is from metal to non-metal, with corresponding changes in bonding and structure. Here some of silicon's properties, e.g. conductivity, could be regarded as anomalous. Aluminium is a metal, yet many of its compounds have mostly covalent character and its oxide is amphoteric, rather than basic.
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updated: 21 February 2008
