Alkali metals - s-elements.On the outer electron layer each has one electron (ns1).The radii of the atoms in the subgroup downwards increases, the ionization energy is reduced, reducing activity as the ability to give the valence electrons of the outer layer increases.

the metals are very active, so in a free state, they do not occur in nature.They can be found in the form of compounds consisting of minerals (sodium chloride NaCl, NaCl ∙ sylvite KCl, Glauber's salt NaSO4 ∙ 10H2O and others) or in the form of ions in seawater.

physical properties of alkali metals



all alkali metals under normal conditions is a silvery-white crystalline material with high thermal and electrical conductivity.They have a body-centered cubic packing (OTSKU).Density, boiling point and melting of metals of g
roup I are relatively low.From top to bottom in the subgroup density increases, and the melting point decrease.

Getting alkali metal



Alkali metals are usually obtained by electrolysis of molten salts (usually chlorides), or alkalis.During electrolysis NaCl melt, for example, is released at the cathode pure sodium and the anode - chlorine gas: 2NaCl (melt) = 2Na + Cl2 ↑.

chemical properties of alkali metals



chemical properties of lithium, sodium, potassium, rubidium, cesium and France - the most active metals and one of the most powerful reducing agents.The reactions are easily donate electrons to the outer layer, becoming positively charged ions.The alkali metal compounds formed by ionic bond prevails.

In the reaction of alkali metals with oxygen as the major product formed peroxides, and as a by - oxides:

2Na + O2 = Na2O2 (sodium peroxide),

4Na + O2 = 2Na2O (sodium oxide).

with halogens they give halides with sulfur - sulfides, hydrogen - hydrides:

2Na + Cl2 = 2NaCl (sodium chloride),

2Na + S = Na2S (sodium sulfide),

2Na + H2 = 2NaH (sodium hydride).

Sodium hydride - unstable compound.It is decomposed by water, giving free hydrogen and alkali:

NaH + H2O = NaOH + H2 ↑.

free hydrogen and alkali are also formed in contact with water alkali metals themselves:

2Na + 2H2O = 2NaOH + H2 ↑.

These metals also react with diluted acids, displacing one hydrogen:

2Na + 2HCl = 2NaCl + H2 ↑.

With organic alkali metal halides interact by Wurtz reaction:

2Na + 2CH3Cl = C2H6 + 2NaCl.