Alkali metals are the family in Group 1 of the periodic table, consisting of the elements lithium, sodium, potassium, rubidium, cesium, and francium.
General Properties
Alkali metals have physical properties similar to general metals: malleable, ductile, lustrous, and conductors of electricity and heat. However, compared to other metals, they have lower melting points, and are less dense. All but lithium float on water. They are also very soft.
Alkali metals have one loosely bound electron in the valence shell so they have the largest atomic radii in the periods. Since they only have one valence electron they have low ionization energies and low electronegativities, and therefore are the most reactive family of metals.
Alkali metals have one loosely bound electron in the valence shell so they have the largest atomic radii in the periods. Since they only have one valence electron they have low ionization energies and low electronegativities, and therefore are the most reactive family of metals.
Group trends
As you go down the group:
- their melting points decrease
- their densities increase
- they become softer
- they become more reactive
If a new alkali metal is discovered which is placed under francium in the periodic table, we can predict from the trends that it will be softest and the most reactive, and that it will have the lowest melting point and highest density.
- their melting points decrease
- their densities increase
- they become softer
- they become more reactive
If a new alkali metal is discovered which is placed under francium in the periodic table, we can predict from the trends that it will be softest and the most reactive, and that it will have the lowest melting point and highest density.
Chemistry The Study of Matter Prentice Hall p.667-8
http://chemistry.about.com/od/elementgroups/a/alkalimetals.htm
http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/periodic_table/groupsrev1.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/patterns/groupsrev2.shtml
http://chemistry.about.com/od/elementgroups/a/alkalimetals.htm
http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/periodic_table/groupsrev1.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/patterns/groupsrev2.shtml