Trends in physical properties of elements in period three
Answer Text: Trends in physical properties of elements in period 3.Electrical conductivity.- Sodium, magnesium and aluminium are good conductors of electricity.Reason:They all have giant metallic structures with delocalized electrons which conduct electricity;- The electrical conductivity increases from sodium to aluminium.Reason:Electrical conductivity increases with increase in the number of delocalized electrons; thus aluminium with the highest number of delocalized electrons (3) in each atom will have the highest electrical conductivity;- In the metals the electrical conductivity decreases with increase in temperature.Reason:- Increase in temperature distorts the alignment of electrons thus preventing their easy flow and hence poor conductivity;- Phosphorus, sulphur, chlorine and argon do not conduct electric current.Reason: They all have molecular structures and all the electrons in the atoms are used in bonding; thus they lack delocalized electron or free ions for electrical conductivity.- Silicon conducts electric current, and its electrical conductivity increases with increase in temperatures.Reason:- It is a semi-conductor; making it a very unique element in this period.Note:- A semi-conductor is a crystalline material which only conducts electricity under certain conditions.
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