Alkaline metals are characterized by high chemical activity. Carry sodium, potassium, caesium to them, frantsy and lithium. They have very low temperature of melting and boiling.
Physical properties of alkaline metals
All alkaline metals, except caesium, have the expressed metal gloss and a silvery shade. Caesium has a golden shade. All of them in a firm state have an objemocentrirovanny cubic lattice with two atoms in a cell. Type of communication of their atoms - metal. It causes their high conductivity. Alkaline metals (except lithium) can be knifed easily. At the room temperature they are almost pastelike.
The piece of caesium can be melted, just holding it in hand. Temperature of melting of this metal is only 29 wasps. The serial number in Mendeleyev's table is lower, the this temperature is higher. Density of all alkaline metals very low. Lithium, the most dense of them, floats in kerosene. Sodium and potassium are capable to float in water.
Chemical properties of alkaline metals
Alkaline metals are characterized by high chemical activity. At atoms of these elements very low values of potentials of ionization. To tear off an electron from a s-cover (to ionize atom), rather small energy is necessary. Optical spectra of alkaline metals possess the brightest lines among all elements of the table of Mendeleyev. The low value of potential of ionization allows to receive easily with their help characteristic light radiation and to register it a spectroscope. Vapors of caesium paint a flame in blue-green color, sodium vapors - in bright yellow. Alkaline metals store in special ampoules under a kerosene layer. Even on air in a near-surface layer of metal the oxidic film is formed. On lithium its nitride appears. Nitrides of other similar metals are not formed. Alkaline these metals are called for their ability to form alkalis at contact with water. These are the caustic substances injuring skin of the person and any fabric. No of alkaline metals can be picked up without gloves. At contact with skin they form alkali. Before work with them it is necessary to study safety measures. Such metals react with the diluted acids. Course of similar reaction can not always be predicted as hydrogen and alkali which then neutralizes acid is formed. Usually reactions with acids are followed by explosion therefore in practice they are not carried out. All alkaline metals by the nature are reducers. They are capable to restore less active metals from their connections. Thus it is possible to receive aluminum from its chloride.