2. ELECTRONIC CONFIGURATION
ALL THE ALKALI METALS HAVE ONE VALENCE
ELECTRON, ns1
eg:Li-1s2 2s1
Na-1s2 2s2 2p6 3s1
THE MOST ELECTROPOSITIVE METALS.

3. ATOMIC AND IONIC RADII
• Alkali metal atoms have largest sizes
• The atomic and ionic radii of alkali metals
increase on moving down the group

4. HYDRATION ENTHALPY
• The hydration enthalpies of alkali metal
ions decrease with increase in ionic sizes
Li+>Na+>K+>Rb+>Cs+

5. PHYSICAL PROPERTIES
• Alkali metals are silvery white, soft and light
metals
• Low density
• Low melting point and boiling points

6. CHEMICAL PROPERTIES
• Alkali metals are highly reactive due to their
large size
• Low ionization enthalpy
• The reactivity of metals increases down the
group

7. REACTIVITY TOWARDS AIR
• Alkali metals in dry air due to the formation
of their oxide
• Lithium forms monoxide
4Li+o2 2Li2o

8. REACTIVITY TOWARDS WATER
• The alkali metals react with water to
form hydroxide and dihydrogen
2M+2H2O 2M++2OH-+H2
(M=an alkali metal)

9. REACTIVITY TOWARDS DIHYDROGEN
• Alkali metals react with dihydrogen to
form hydrides
2M+H2 2M+H-

10. REACTIVITY TOWARDS HALOGENS
• Alkali metals react with halogens to
form ionic halide

11. USES
• Lithium metal bearing for motor
engines.
• Aluminium to make aircraft parts.
• Lithium also used to make
electrochemical cells.
• Potassium chloride is used as fertilizer.