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Lithium, 3Li
Lithium paraffin.jpg
Lithium floating in oil
Pronunciation /ˈlɪθiəm/ (LITH-ee-əm)
Appearance silvery-white
Standard atomic weight Ar, std(Li) [6.9386.997] conventional: 6.94
Lithium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z) 3
Group group 1: hydrogen and alkali metals
Period period 2
Block   s
Electron configuration [He] 2s1
Electrons per shell 2, 1
Physical properties
Phase at STP solid
Melting point 453.65 K ​(180.50 °C, ​356.90 °F)
Boiling point 1603 K ​(1330 °C, ​2426 °F)
Density (near r.t.) 0.534 g/cm3
when liquid (at m.p.) 0.512 g/cm3
Critical point 3220 K, 67 MPa (extrapolated)
Heat of fusion 3.00 kJ/mol
Heat of vaporization 136 kJ/mol
Molar heat capacity 24.860 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 797 885 995 1144 1337 1610
Atomic properties
Oxidation states +1 (a strongly basic oxide)
Electronegativity Pauling scale: 0.98
Ionization energies
  • 1st: 520.2 kJ/mol
  • 2nd: 7298.1 kJ/mol
  • 3rd: 11815.0 kJ/mol
Atomic radius empirical: 152 pm
Covalent radius 128±7 pm
Van der Waals radius 182 pm
Color lines in a spectral range
Spectral lines of lithium
Other properties
Natural occurrence primordial
Crystal structure body-centered cubic (bcc)
Body-centered cubic crystal structure for lithium
Speed of sound thin rod 6000 m/s (at 20 °C)
Thermal expansion 46 µm/(m⋅K) (at 25 °C)
Thermal conductivity 84.8 W/(m⋅K)
Electrical resistivity 92.8 nΩ⋅m (at 20 °C)
Magnetic ordering paramagnetic
Molar magnetic susceptibility +14.2·10−6 cm3/mol (298 K)
Young's modulus 4.9 GPa
Shear modulus 4.2 GPa
Bulk modulus 11 GPa
Mohs hardness 0.6
Brinell hardness 5 MPa
CAS Number 7439-93-2
Discovery Johan August Arfwedson (1817)
First isolation William Thomas Brande (1821)
Main isotopes of lithium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
6Li 5% stable
7Li 95% stable
6Li content may be as low as 3.75% in
natural samples. 7Li would therefore
have a content of up to 96.25%.

Lithium (from Greek lithos 'stone') is a soft, silver-white metal with symbol Li. It is the third chemical element in the periodic table. This means that it has 3 protons in its nucleus and 3 electrons around it. Its atomic number is 3. Its mass number is 6.94. It has two common isotopes, 6Li and 7Li. 7Li is more common. 92.5% of lithium is 7Li. Lithium is a soft silvery metal that is very reactive. It is used in lithium batteries and certain medicines.


Physical properties

Lithium is one of the alkali metals. Lithium is a silvery solid metal (when freshly cut). It is very soft. Thus it can be cut easily with a knife. It melts at a low temperature. It is very light, similar to wood. It is the least dense metal and the least dense element in a solid or liquid state. It can hold more heat than any other solid element. It conducts heat and electricity easily.

Chemical properties

It will react with water, giving off hydrogen to form a basic solution (lithium hydroxide). Because of this, lithium must be stored in petroleum jelly. Sodium and potassium can be stored in oil but lithium cannot because it is so light. It will just float on the oil and not be protected by it.

Lithium also reacts with halogens. It can react with nitrogen gas to make lithium nitride. It reacts with air to make a black tarnish and then a white powder of lithium hydroxide and lithium carbonate.

Chemical compounds

Flame test for lithium

Lithium forms chemical compounds with only one oxidation state: +1. Most of them are white and unreactive. They make a bright red color when heated in a flame. They are a little toxic. Most of them dissolve in water. Lithium carbonate is less soluble in water than the other alkali metal carbonates like sodium carbonate.


It does not occur as an element in nature. It only is in the form of lithium compounds. The ocean has a large amount of lithium in it. Certain granites have large amounts of lithium. Most living things have lithium in them. There are some places where much lithium is in the salt. Some silicates have lithium in them.


Lithium (Greek lithos, meaning "stone") was discovered by Johann Arfvedson in 1817. In 1818, Christian Gmelin observed that lithium salts give a bright red color in flame. W.T. Brande and Sir Humphrey Davy later used electrolysis on lithium oxide to isolate the element. Lithium was first used in greases. Then nuclear weapons became a big use of lithium. Lithium was also used to make glass melt easier and make aluminium oxide melt easier in making aluminium. Now lithium is used mainly in batteries.

It was apparently given the name "lithium" because it was discovered from a mineral, while other common alkali metals were first discovered in plant tissue.


It is made by getting lithium chloride from pools and springs. The lithium chloride is melted and electrolyzed. This makes liquid lithium and chlorine.


As an element

Its main use is in batteries. Lithium is used as an anode in the lithium battery. It has more power than batteries with zinc, like alkaline cells. Lithium ion batteries also have lithium in them, though not as an element. It is also used in heat transfer alloys. Lithium is used to make organolithium compounds. They are used for very strong bases.

It is used to make special glasses and ceramics, including the Mount Palomar telescope's 200 inch mirror. Lithium is the lightest known metal and can be alloyed with aluminium, copper, manganese, and cadmium to make strong, lightweight metals for aircraft.

In chemical compounds

Lithium compounds are used in some drugs known as mood stabilizers. Lithium niobate is used in radio transmitters in cell phones. Some lithium compounds are also used in ceramics. Lithium chloride can absorb water from other things. Some lithium compounds are used to make soap and grease. Lithium carbonate is used as a drug to treat manic depression disorder. Lithium carbonate is used for the treatment of bipolar disease and other mental illness conditions.

Organic chemistry

Organolithium compounds are used to make polymers and fine chemicals. Many lithium compounds are used as reagents to make organic compounds. Some lithium compounds like lithium aluminium hydride, lithium triethylborohydride, n-butyllithium and tert-butyllithium are commonly used as very strong bases called superbases.

Other uses

Lithium compounds are used as pyrotechnic colorants and oxidizers in red fireworks and flares. Lithium chloride and lithium bromide are used as desiccants for gas streams. Lithium hydroxide and lithium peroxide are used to remove carbon dioxide and purify the air in spacecrafts and submarines. Lithium hydroxide, lithium peroxide and lithium perchlorate are used in oxygen candles that supply submarines with oxygen.

Lithium aluminum hydride can also be used as a solid fuel by itself. Lithium hydride that contains lithium-6 is used in thermonuclear weapons.


Lithium reacts with water, making irritating smoke and heat. It is not as dangerous as the other alkali metals. Lithium hydroxide is very corrosive.


There are 5 isotopes of Lithium having respectively 2, 3, 4, 5 and 6 neutrons in the nucleus. The most common isotope in nature is 3Li7 which makes up 92.58 % of the total. The second isotope which is widely available is 3Li6 which makes up 7.42 % of the total. The other 3 isotopes exist in very small quantities. The atomic mass of Lithium is 6.939.

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Kids robot.svg In Spanish: Litio para niños

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