The alkaline earth metals are a number of elements composed of Group 2 (IUPAC style) (Group IIA) from the periodic table: magnesium (Mg), beryllium (Be), strontium (Sr), calcium (Ca), radium (Ra) and barium (Ba). This specific group within the periodic table owes its name for their oxides that merely give basic alkaline solutions. These oxides melt at such higher temperature that they stay solids (earths) in fires. The alkaline earth metals give a great example of group trends in properties in the periodic table, with properly characterized homologous behavior down the group. With the exception of Mg and Be, the metals possess a distinguishable flame color, bright red for Sr, orange for Ca, crimson red for Ra and green for Ba.
The alkaline earth metals are called after their oxides, the alkaline earths, whose old-fashioned titles were magnesia, beryllia, strontia, lime and baryta. These oxides tend to be basic (alkaline) when mixed with water. Earth is an old word applied by early chemists to nonmetallic substances which are insoluble in water and resistant to heating properties discussed by these oxides.
The alkaline earths are the elements positioned in Group IIA of the periodic table. Properties: The alkaline earths have many of the characteristic properties of the metals. Alkaline earths possess low electronegativities and low electron affinities. As with the alkali metals, the properties rely on the ease with which electrons are lost. The alkaline earths possess two electrons within the outer shell. They have smaller atomic radii compared to the alkali metals. The two valence electrons are not tightly bound to the nucleus, therefore the alkaline earths easily lose the electrons to make divalent cations.
Summary of Common Properties:
Low electron affinities
Two electrons in the outer shell
Readily form divalent cations.
The alkaline earth metals are in the 2nd group of the periodic table. Several characteristics of alkaline earth metals are:
Not found freely in nature
An oxidation number of +2 which makes them very reactive
Distributed in rock structure
Present in the earth's crust but not in their basic form
High boiling points
Two electrons in their outer shell
High melting points
Low electron affinity
Silver in color
React easily with the halogens and water
Softer and stronger than most other metals (except the alkali metals)
The alkaline earth metals are: