1. By: Faraz Class: 9B Block 8 Chemistry
Alkaline Earth Metals
By: Faraz
Class: 9B
Block 8 Chemistry

2. What are “Alkaline Earth Metals”?
Alkaline Earth metals are metallic elements found in the 2nd group of the periodic table.
This is the list of all alkali earth metals:
-Beryllium
-Magnesium
-Calcium
-Strontium
-Barium
-Radium
They are placed in the periodic table next to the Alkali Metal group.

3. Why are they called Alkaline earth metals?
They are mainly called alkaline earth metals because they are found in the earth’s crust. They are distributed in rock structures.

4. Details of the elements
Symbol
Atomic
Number
Melting Point /K
Density/kg m-3
Beryllium Be 4
1551
1847
Magnesium Mg 12
922
1738
Calcium Ca 20
1112
1550
Strontium Sr 38
1042
2540
Barium Ba 56
1002
3594
Radium Ra 88
973
5000

5. Physical Properties They are malleable (soft)
They are lustrous (shiny)
They have low densities (able to float on water)
Good conductor of heat and electricity
Low melting and boiling points
They have almost all the same properties that alkali metals have

6. Chemical Properties
The alkaline earth metals are high in the reactivity series of metals, but not as high as the alkali metals of Group 1.
Due to their high levels of reactivity, the alkaline earth metals rarely appear by themselves in nature; rather, they are typically found with other elements in compound form, often as carbonates or sulfates. This, again, is another similarity with the alkali metals. But whereas the alkali metals tend to form 1+ cations (positively charged atoms), the alkaline earth metals form 2+ cations—that is, cations with a positive charge of 2.
As you go down the table they get more reactive.
They react with water and air.
All alkaline earth elements have an oxidation number of +2, making them very reactive.

7. Reactions with Water
When added to water, the first alkaline earth metal (Beryllium) is totally unreacative, and doesn't even react with steam. Then as you move down the group, the reactions become increasingly vigourous.
Example:-
-Mg + H2O → MgO + H2
-Ca(s) + H2 → CaH2

8. Reactions with Air
The reactivity towards oxygen increases as we go down the group. Thus Ca, Ba and Sr are stored in paraffin but Be and Mg are not because they form protective oxide layer on their surface.
Example:-
-2Be + O2 (air) → 2BeO
-Mg + air → MgO + Ng3N2

9. Discovery
Beryllium was discovered by Nicholas Louis Vauquelin in 1797.
Magnesium was discovered by Sir Humphrey Davy in 1808.
Calcium was discovered by Sir Humphrey Davy in 1808.
Strontium was discovered by Adair Crawford in 1790.
Barium was discovered by Sir Humphrey Davy in 1808.
Radium was discovered by Pierre and Marie Curie in 1898.