2 - 11 The alkali metals
● ***Low\ering melting and boiling points down the group
● ***Increasing densities down the group (although not regularly) [Li, Na and K are less
dense than water, thus float on it]
● ***Very soft, easily cut with knife; increasing softness down the group
● ***Shiny, silver when freshly cut, tarnish very quickly in air exposure (more quickly
down the group)
● ***Increasing reactivity down the group (all react quickly with oxygen in air, forming
oxides with formula M*2O; all react rapidly with water, forming strongly alkaline
solutions of corrosive metal hydroxides [with formula M*OH] and hydrogen
[gas])
● ***Stored under oil, preventing exposure to oxygen/water
● ***All have one outer shell electron
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● ***Low\ering melting and boiling points down the group
● ***Increasing densities down the group (although not regularly) [Li, Na and K are less
dense than water, thus float on it]
● ***Very soft, easily cut with knife; increasing softness down the group
● ***Shiny, silver when freshly cut, tarnish very quickly in air exposure (more quickly
down the group)
● ***Increasing reactivity down the group (all react quickly with oxygen in air, forming
oxides with formula M*2O; all react rapidly with water, forming strongly alkaline
solutions of corrosive metal hydroxides [with formula M*OH] and hydrogen
[gas])
● ***Stored under oil, preventing exposure to oxygen/water
● ***All have one outer shell electron
1
