Alkaline earth metals reactions - s block group 2 elements
The general electronic configuration of alkaline metals is [noble gas] ns2 where n represents
the valence shell. These metals forms +2 ions.
Elements of Alkaline earth metals
- Beryllium (Be)
- Magnesium (Mg)
- Calcium (Ca)
- Strontium (Sr)
- Barium (Ba)
- Radium (Ra)
Occurrence of Alkaline earth metals
Occurrence of Magnesium (Mg)
Occurrence of Calcium (Ca)
- In vast sedimentary rocks of CaCO3 existing as awhole mountain ranges of limestone, marble and
- As Gypsum ( CaSO4.2H2O )
- As fluorite (CaF2)
- As fluoroapatite ( 3Ca3(PO4)2.CaF2 )
Chemical properties of Alkaline earth metals
Reactions of water and alkaline earth metals
Alkaline earth metals react in lesser tendency with water when it compares with
- Be and Mg don't react with cold water.
- Mg react with steam. But Be does not.
- Ca, Sr and Ba react with water and form hydroxides and hydrogen gas.
Hydroxides of alkaline earth metals' are basic. Also basic strength increases down the family.
Ex: Sr(OH)2 is more basic than Ca(OH)2.
Reactions between air and alkaline earth metals
Air contains O2 and N2 gases. Alkaline earth metals reacts with O2 and N2
in different ways.
- Due to formation of film of oxides of Be and Mg they do not continously react with O2.
But powdered Be burns and gives BeO and Be3N2
- When Mg burns in air and give a mixture of MgO and Mg3N2.
- Ca, Sr and Ba easily react with air give oxides and nitrides.
Uses of alkaline earth metals
Now we are going to discuss uses of each element in 2nd group.
Uses of Be
- For manufacturing of many alloys. As an example, copper beryllium alloys are used in the preparation of high strength springs.
- Metallic beryllium is used for making windows of X-ray tubes.
Uses of Mg
- Mg is the lightest constructional metal in industry having a density less than two thirds of Al.
- For manufacturing alloying metals.
- For cathodic protection of other metals as oxygen scavenger.
- The compounds of magnesium such as Mg(OH)2 and MgCO3 are used in making tooth pastes.
- Mg is used as a dioxidizer for removing last traces of oxygen from Cu, steel,etc.
Uses of plaster of paris
- for producing moulds for pottery, ceramics, etc
- used for making statues, models and other decorative materials.
- It is used in the building industry as well as plasters.
- In dentistry
- Plaster of paris is used in surgical bandages known as plasters for setting broken and fractured bones in the
body because it immoblises the affected part of the organ where there is a bone fracture or sprain.