The Periodic Table
ALKALI METALS
The group 1 elements are called the alkali metals. They are found in
the s-block of the periodic table. They are very reactive, and as such
not found free in nature but in a combined state. They are stored in oil
to prevent them from reacting with the oxygen and water vapour in
the air
Physical Properties of Group 1
•
They exist as silvery white solid at room temperature
•
They are soft and light
•
They have low melting and boiling point which decreases as you
move down the group
•
They are very good conductors of heat and electricity
Chemical properties

They are univalent

They ionize very readily to form positive ions by donating electrons,
hence they are good reducing agent. The reducing property increases
down the group. Example ; Na ----- e-  Na+
K ------ e-  K+

They react with cold water vigorously to liberate hydrogen gas and
form metal hydroxides; so they are known as the alkali metals. K(s) +
2H2O(l)  2KOH(aq) + H2

They form basic oxides when react with oxygen, these oxides also
dissolve in water to form very strong alkalis. For instance; Na(s) + O2(g) 
2Na2O (s)
Na2O + H2O  NaOH

Their trioxonitrates (IV) decomposes upon heating to form
dioxonitrate (III) salts and oxygen KNO3  2KNO2 + O2

Their trioxocarbonate (IV) withstand heating but their hydrogen
trixocarbonate (IV) decomposes to give trioxocarbonate (IV),
carbon (IV) oxide and water . E.g NaHCO3  Na2CO3 +CO2 + H2O
Electronegativity: this is the power of an atom in a molecule to attract
electrons. Electronegativity decreases down the group, due to
increasing distance between the valence electrons and nucleus.
Across the period there is a steady increase in electronegativity =, due
to decreasing distance between the valence electrons amd the
nucleus.
Ionization energy: this is the energy absorbed in order to remove the
outermost electron from a gasesous atom. Ionization energy decreases
steadily down the group, due to the steady increase in atomic size , as
the electron to be removed is not strongly bound to the nucleus.
Hence it will be easier to remove the outermost electron in K(2,8,8,1)
than in the case of lithium (2,1). Across the period, ionization energy
decreases in atomic size, as the electron to be remo