Alkali Metals

Alkali metals intrigues me...
Flame appears when they are thrown into water..... 

http://www.planet-scicast.com/_db/_images/SciCast-T2333-The_Alkali_Metals-Thumb.jpg

Alkali metals are extremely reactive metals with only one valence electron*, making easy for them to donate the valence electron and form an ionic bond with oxygen. The result is an ionic compound with lower energy level.
*Valence electrons are electrons on the outermost orbit of an atom.

http://visual.merriam-webster.com/images/science/chemistry/chemical-elements/alkali-metals.jpg

The alkali metals are: Lithium, sodium, potassium, rubidium, caesium, francium....(in the order of the periodic table)

The reactivity of these metals increases as we go down the periodic table, with the least reactive metal being Lithium and the most reactive metal being francium.

One of the most notable things about alkali metal is its ability to undergo "combustion" in cold water, releasing heat and light energy.

This property makes alkali metal interesting to study at because most reactive metals need to be burnt to oxidize it. For example, magnesium undergoes a vigorous reaction with oxygen when it is burnt, but potassium burns with bright lilac flame when it is in contact with water.

http://people.virginia.edu/~har4y/storyboard/sodium_soft.jpg

While the reaction between lithium, sodium and potassium could be done in a school lab, rubidium and caesium reactions are not allowed to be done in school. Francium, on the other hand, is radioactive, an will only exist for few seconds in microscopic quantities, therefore, not enough to produce a reaction.

The video below is an interesting educational video I've found on youtube about rubidium and caesium reaction:





thats what science is all about!!