In 1817, a met­al of the first group of the sec­ond pe­ri­od in the
pe­ri­od­ic ta­ble was dis­cov­ered – lithi­um. The dis­cov­ery was made by the Swedish sci­en­tist Jo­hann Au­gust Ar­fwed­son, who was
in­ves­ti­gat­ing var­i­ous min­er­als. The el­e­ment was found in petal­ite,
spo­dumene and lep­i­do­lite. Short­ly af­ter­wards, in 1818, metal­lic
lithi­um was ob­tained by Humphrey Davy. Lithi­um and its
com­pounds are es­sen­tial chem­i­cal el­e­ments in the life of hu­man be­ings, and are used in many spheres of in­dus­try; in the man­u­fac­ture of chem­i­cal sources of elec­tri­cal en­er­gy; and in the man­u­fac­ture of fire­works. Lithi­um is an al­ka­line met­al of a sil­very-white
col­or. It is soft and eas­i­ly mold­ed, and a cube of metal­lic lithi­um can be cut with a knife.

It is in­ter­est­ing that lithi­um is the only met­al from this group which boils and melts at rather high tem­per­a­tures 180 de­grees Cel­sius re­spec­tive­ly. But it is also in­ter­est­ing that com­pared with its “al­ka­line neigh­bors”, lithi­um has the low­est den­si­ty – half the den­si­ty of wa­ter. This prop­er­ty means that lithi­um does not even sink in kerosene. Re­ac­tion of lithi­um and sul­fu­ric acid:
If a small piece of lithi­um is added to con­cen­trat­ed sul­fu­ric acid, lithi­um sul­fate, hy­dro­gen sul­fide and wa­ter form.

Warn­ing! "Do not re­peat this ex­per­i­ment. " (The reaction is highly exothermic)

This re­ac­tion is dan­ger­ous, as lithi­um im­me­di­ate­ly burns with a bright red flame:

8Li + 5H₂­SO₄ → 4Li₂­SO₄ + Н₂S + 4H₂O

With di­lut­ed sul­fu­ric acid, lithi­um in­ter­acts with the for­ma­tion of lithi­um sul­fate and hy­dro­gen.

2Li + H₂­SO₄ → Li₂­SO₄ + Н₂

" . . . . And as always, thanks for watching. "

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