Notes On Alkaline Earth Metals: General Characteristics And Properties - CBSE Class 11 Chemistry



The elements in group 2 of the periodic table are called the alkaline earth metals. The alkaline earth metals all have two valence electrons and form +2 cations.

The alkaline earth metals are silvery white, lustrous (or) shiny solids, although beryllium and magnesium may have a greyish cast to them.  They are relatively soft metals, though harder than the alkali metals. 

These are good conductors of heat and electricity. The group 2 metals have higher boiling points than the group 1 metals due to their smaller atomic radii. Many salts of the alkaline earth metals are found as hydrates.

In flame tests, calcium gives a brick-red flame, strontium produces a crimson flame and barium gives an apple-green colour.

Magnesium and beryllium do not react with water, because both the metals form an oxide layer on their surfaces. Calcium, strontium and barium all react with water to form hydroxides. 
Ca+ H2O → Ca(OH)2
Sr+ H2O →Sr(OH)2
Ba+ H2O → Ba(OH)2

The alkaline earth metals form a variety of compounds, including oxides, hydroxides, halides, carbonates, sulphates and nitrates.




The alkaline earth metals react with acids to release hydrogen gas.



The alkaline earth metals are good reducing agents. Carbonates group2 decomposes into metal oxide and Carbon dioxide on heating.

Summary




The elements in group 2 of the periodic table are called the alkaline earth metals. The alkaline earth metals all have two valence electrons and form +2 cations.

The alkaline earth metals are silvery white, lustrous (or) shiny solids, although beryllium and magnesium may have a greyish cast to them.  They are relatively soft metals, though harder than the alkali metals. 

These are good conductors of heat and electricity. The group 2 metals have higher boiling points than the group 1 metals due to their smaller atomic radii. Many salts of the alkaline earth metals are found as hydrates.

In flame tests, calcium gives a brick-red flame, strontium produces a crimson flame and barium gives an apple-green colour.

Magnesium and beryllium do not react with water, because both the metals form an oxide layer on their surfaces. Calcium, strontium and barium all react with water to form hydroxides. 
Ca+ H2O → Ca(OH)2
Sr+ H2O →Sr(OH)2
Ba+ H2O → Ba(OH)2

The alkaline earth metals form a variety of compounds, including oxides, hydroxides, halides, carbonates, sulphates and nitrates.




The alkaline earth metals react with acids to release hydrogen gas.



The alkaline earth metals are good reducing agents. Carbonates group2 decomposes into metal oxide and Carbon dioxide on heating.

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