Lithium facts for kids

Kids Encyclopedia Facts


silvery-white (shown floating in oil)

Spectral lines of lithium
General properties
Name, symbol, number lithium, Li, 3
Pronunciation /ˈlɪθiəm/ LI-thee-əm
Element category alkali metal
Group, period, block 1, 2, s
Standard atomic weight 6.94(1) g/mol
Electron configuration [He] 2s1
Electrons per shell 2, 1 (Image)
Physical properties
Phase solid
Density (near r.t.) 0.534 g/cm3
Liquid density at m.p. 0.512 g/cm3
Melting point 453.69 K, 180.54 °C, 356.97 °F
Boiling point 1615 K, 1342 °C, 2448 °F
Critical point (extrapolated)
3223 K, 67 MPa
Heat of fusion 3.00 kJ/mol
Heat of vaporization 147.1 kJ/mol
Specific heat capacity (25 °C) 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
(strongly basic oxide)
Electronegativity 0.98 (Pauling scale)
Ionization energies 1st: 520.2 kJ/mol
2nd: 7298.1 kJ/mol
3rd: 11815.0 kJ/mol
Atomic radius 152 pm
Covalent radius 128±7 pm
Van der Waals radius 182 pm
Crystal structure body-centered cubic
Magnetic ordering paramagnetic
Electrical resistivity (20 °C) 92.8 nΩ·m
Thermal conductivity (300 K) 84.8 W/(m·K)
Thermal expansion (25 °C) 46 µm/(m·K)
Speed of sound (thin rod) (20 °C) 6000 m/s
Young's modulus 4.9 GPa
Shear modulus 4.2 GPa
Bulk modulus 11 GPa
Mohs hardness 0.6
CAS registry number 7439-93-2
Most stable isotopes
Main article: Isotopes of lithium
iso NA half-life DM DE (MeV) DP
6Li 7.5% 6Li is stable with 3 neutrons
7Li 92.5% 7Li is stable with 4 neutrons
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 used first 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.

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 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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Lithium Facts for Kids. Kiddle Encyclopedia.