The+Alkali+Metals

__Chemical Properties__
The Alkali Metals: Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Caesium(Cs) ==

==

Lithium 2,1 Sodium 2,8,1 Potassium 2,8,8,1 Rubidium 2,8,18,8,1 Caesium 2,8,18,18,8,1 Francium 2,8,18,32,18,8,1
 * __Metals__**
 * __Electron Configuration__**
 * __Electron Configuration__**
 * __Electron Configuration__**

__As you go down the group:__

- The melting and boiling points decrease. - More electron shells are added, causing the atoms and atomic radius to be bigger. - The density increases. - The hardness of the atom decreases. - The elements become more reactive.

- They are the most electropositive (least electronegative elements) elements in the periodic table. They react with a great variety of nonmetals, forming ionic compounds which are usually soluble white solids.

- Since they all have one valence electron, they all behave in a chemically similar way.

- They are very reactive metals and must be stored under oil to help minimize the reaction with oxygen or water vapour in the air.

- They are good conductors of heat and electricity and have high boiling points.

- When an alkali metal atom reacts, it loses an electron (oxidation) to form a single positively charged ion eg

> Na+ + e-. In terms of electrons 2.8.1
> 2.8 and so forming a stable ion with a noble gas electron arrangement.

- The first three have a lower density and can float on water; therefore they have little material strength.

- The reaction of alkali metals and water is very exothermic, fast, and violent.

- Since there is an increase of electron shells, the outer electron is further away from the nucleus and is protected by the extra full shell of negative charge. Therefore the outer electron is not as strongly held by the positive nucleus as the positive charge is decreased. This means that the outer electron is more easily lost, allowing the element to be more reactive.

=**__Interesting Facts about Alkali Metals__**=

//Lithium// – Discovery: 1817 by Johann Arfvedson. Used for batteries, ceramics and lubricants. Also used in medical fields, as it is known to have a mood-stabilizing effect. //Sodium// – Discovery: 1807 by Sir Humphrey Davy. Used for medicine and agriculture. Used in certain nuclear reactors because of excellent heat/metal conductivity, also used in street lamps due to orange-yellow energized vapour. //Potassium// – Discovery: 1807 by Sir Humphrey Davy. Used for glass and soap. It is also a mineral needed for the human body – at least 2,000 milligrams per day. //Rubidium// – Discovery: 1861 by R. Bunsen. Used for catalysts and photocells. //Cesium// – Discovery: 1860 by Fustov Kirchoff. Removes air traces in vacuum tubes. //Francium// – Discovery: 1939 by Marguerite Derey. Has no uses.

//Interesting Facts:// Very reactive metals – Only have one valence electron, therefore they are ready to lose that electron through ionic bonding with other elements. Alkali metals are malleable, ductile, and conduct heat/electricity well. They are softer than most metals. Cesium and Francium are the most reactive in the group. Alkali metals will react violently with water to release hydrogen gas, either fizzing around, making bubbles or igniting. They are never found in nature – they are stored under mineral oil.