ALKALI METALS
What are alkali metals? Alkali metals are metals in the periodic table which forms group1, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr), ordered by the least reactive to the most. The alkali metals get down in the periodic table, its reactivity increases. Although hydrogen (H) is also in that group, it is not counted as an alkali metal. But, under the high pressure and temperature of Saturn and Jupiter, hydrogen exists as a metal, and has the properties of alkali metals. Alkali metals have 1 electron in its outmost electron shell, which means the only way of achieving the equivalent of filled outmost electron shells is to give one electron to an element with high electro negativity, resulting in a singly charged positive ion. Alkali metals are soft metals with low densities. All of them with an exception of one, caesium with a tint of gold, have a silvery colour. Alkali metals can bond with hydrogen oxide (H2O), commonly known as water, without the presence of additional heat energy in room temperature. Alkali metals are highly reactive with water, so reactive that it is pyrophoric [1]. Because of this, alkali metals are usually submerged with oil, as oil is not soluble in water, thus no moisture can reach the metal and react. The reaction would produce a compound. Due to this ultra-sensitive reaction, alkali metals do not occur naturally, but exists in various compounds.
Alkali metal + hydrogen oxide= Alkali metal hydroxide + Hydrogen gas
Eg. Rubidium + hydrogen oxide = Rubidium hydroxide + Hydrogen gas

Lithium
Lithium is the lightest and least dense solid metal (in room temperature), and the least reactive alkali metal (not including hydrogen metal). It exposes a shiny layer when cut open but quickly dulls when contacted with oxygen. Lithium exists naturally as lithium chloride (LiCl). It can be extracted from igneous [2] rocks like granite and pegmatite. It can also be extracted from hectorite and even seawater. Lithium is a flammable metal, and the fires are very hard to extinguish. Lithium is used in many ways, the most common, Lithium-ion batteries. A typical cell of Lithium-ion battery can generate 3 volts compared to 2.1 volts of lead/acid and 1.5 of zinc carbon cells. Due to its low atomic mass, it has a high charge-to-weight and power-to-weight ratio. Lithium is also used in medical terms as mood stabilisers. Lithium also has a high heat capacity [3], and this property makes it a good lubricant, and is also mixed into ceramics. Lithium is alloyed with aluminium, cadmium, copper and manganese are used to make high-performance aircraft parts. Bahnmetall consists of lead containing 0.04% lithium, 0.7% calcium and 0.6% sodium is harder than pure lead and was used for railroad car bearings in Germany. Lithium hydroxide is used in space vehicles to absorb carbon-dioxide.
Density (near r.t.) 0.534 g•cm−3
Melting point 453.69 K, 180.54 °C
Boiling point 1615 K, 1342 °C 

Sodium
Sodium is the most common alkali metal, a it is soluble in water, and present in the oceans and organic matter. Sodium, like all other alkali metal, does not occur naturally, as it oxidizes quickly in air and is reactive with water. The natural sodium exists as a compound, which is stabilised by chloride, like some other alkali metals, forming sodium chloride. Sodium ions together with potassium ions, produce a charge in our cell membranes producing our nerve impulses. Sodium is so important to living things that land herbivores develop specialized taste receptors for sodium ions. Sodium chloride (NaCl) better known as common salt, and Sodium bicarbonate (NaHCO3) are all common sodium compounds in our daily lives. Sodium accounts for 2.6% of the total weight of our earth’s crust, making it the sixth most abundant mineral, also the most abundant alkali metal. Sodium can be extracted evaporite minerals [4], and Albite (NaAlSi3O8). The old process of producing sodium dates back to 1855, a process named the Deville process. The process involves thermal reduction of sodium carbonate (Na2CO3)and carbon at 1100°C, to separate the sodium from the other elements. Now sodium is produced through electrolysis [5]. The sodium chloride is mixed with calcium chloride, to lower its melting point to 700°C. The end product would not contain any calcium as calcium is less electropositive [6]. Sodium is used commercially in alloys, to smooth out metals and to separate elements from compounds like potassium and zirconium. The alloy of sodium and potassium is used as a heat transfer agent and chemical reducing agent.
Deville process: Na2CO3 (liquid) + 2 C (solid) → 2 Na (vapor) + 3 CO (gas)
Density (near r.t.) 0.968 g•cm−3
Melting point 370.87 K, 97.72 °C,  
Boiling point 1156 K, 883 °C,

Potassium
Potassium only occurs naturally as ionic salts. Potassium ions are found dissolved in seawater, in living things. Potassium ions are essential for the function of living cells and are found in high concentrations in plants and highest in fruits. Potassium is the second least dense metal followed by lithium. Potassium accounts for 1.5% of the total weight of the earth’s crust, making it the seventh most abundant element, and the second most abundant alkali metal, followed by sodium. Potassium is produced by electrolysis of its hydroxide, potassium hydroxide (KOH), also a product of the reaction of water and potassium, (+hydrogen gas) or from evaporite minerals like Carnallite, or potassium magnesium chloride (KMgCl3), Langbeinite (K2Mg2(SO4)3 ), Polyhalite (K2Ca2Mg(SO4)4•2(H2O)) and Sylvite, or potassium chloride (KCl). Potassium reaction is so violent that the heat involved in it is sufficient to ignite the hydrogen gas produced. Potassium is used as fertilizer, in its compounds like potassium chloride (KCl), potassium sulfate (K2SO4 ) or potassium nitrate (KNO3). In fact, 93% of all potassium production is used for fertilizer manufacture. Potassium nitrate is also the oxidizer of modern smokeless gunpowder, replacing saltpetre, the product of fermented cow manure that gives out a huge puff of poisonous gas when ignited. The other 2 ingredients for gunpowder are 16% sulphur and 14% charcoal. As above mentioned, potassium is alloyed with sodium (NaK) to form a heat transfer agent and chemical reducing agent.
Density (near r.t.) 0.89 g•cm−3
Melting point 336.53 K, 63.38 °C 
Boiling point 1032 K, 759 °C

Rubidium
Rubidium is the twenty-third most abundant element on earth. Rubidium is also one of the five metals that are liquid in room temperature. Rubidium can be found in many potassium containing minerals like pollucite ((Cs,Na)2Al2Si4O12•2H2O)) and carnallite. It is also found in lepidolite ((KLi2Al(Al,Si)3O10(F,OH)2 ) a mineral containing caesium and rubidium. Rubidium can be produced by reducing [7]
rubidium chloride with calcium. Rubidium can be used in ion thrusters for space vehicles, as it easily ionized [8], although xenon and caesium does a better job. It can also be used as a getter [9] in vacuum tubes.
Density (near r.t.) 1.532 g•cm−3
Melting point 312.46 K, 39.31 °C
Boiling point 961 K, 688 °C

Caesium
Caesium is a liquid in room temperature, and has the second lowest melting point of any metal followed by mercury. Caesium is a ductile, soft and low density metal. Caesium is also a rather rare element, with only 3 parts per million of the earth’s crust, making it the 45th most common element, and the 36th most common metal. Caesium is found naturally in pollucite, containing iron, rubidium, caesium and calcium. It can also be extracted from pezzottaite (Cs(Be2Li)Al2Si6O). Caesium can be extracted by electrolysis of caesium cyanide (CsCN). Caesium is used in atomic clocks, the most accurate clocks in the world. Atomic clocks detect and define 9,192,631,770 cycles of radiation of the caesium-133 atom as the SI (Standard International) unit of time, seconds. Caesium can also be used an ion thrusters as above mentioned.
Density (near r.t.) 1.93 g•cm−3
Melting point 301.59 K, 28.44 °C  
Boiling point 944 K, 671 °C

Francium
Francium is the most reactive alkali metal, and the only metal that is not assessable to the public because of its high reactivity and rarity. Francium has one of the lowest of all known electronegativity rates. It is also the second rarest of all elements on earth. Only twenty to thirty grams of francium is present in the earth’s crust in any one time. The largest amount of francium ever harvested in one time was about ten thousand atoms. There are no commercial use for francium, but only used for study and experimentations. Francium is only present in thorium and traces can be found in uranium. Thorium is about three to four times more common than uranium, and is counted as a waste metal in rare earth mining, making it cheap and in huge amounts. Despite the fact of its abundance, francium is still a scarce element as it could only be produced by nuclear reaction.
Density (near r.t.) 11.7 g•cm−3
Melting point 2115 K, 1842 °C
Boiling point 5061 K, 4788 °C



[1]Pyrophoric: Would react chemically and ignite if exposed to earth’s air
conditions, usually with water vapour.

[2]Igneous: One of the three main types of rocks on the earth’s crust, formed
by solidified magma or lava.

[3]Heat capacity: Heat capacity is defined as how much heat is needed to raise a
matter by 1 °C

[4] Evaporite Minerals: The leftover soluble sediments of evaporated water

[5]Electrolysis: Electrolysis is a process where electricity is introduced to an
ionic substance, either molten or dissolved in a suitable solvent,
driving an otherwise non-spontaneous chemical reaction to
separate elements from compounds.

[6]Electropositivity: Electro positivity is the ability of elements to lose their
elements, mainly a metal attribute, which means that the
greater metallic character of the element, the higher its
electro positivity, which in turn means that alkali metals are
the most electro positive as above mentioned, they only
have 1 electron on its outer electron shell, and it is easily
lost.

[7]Reducing: A decrease in oxidation state by a molecule, atom, or ion.


[8]Ionize: To convert an atom or molecule into ions by adding or removing
charged particles like electrons or other ions.

[9]Getter: Reactive materials used to remove traces of gas from vacuums.