When the alkali metals are cut, they initially appear shiny grey but quickly become dull and white as they react with oxygen in the air. This is known as tarnishing. Sodium tarnishes more quickly ...

Many metals react with oxygen to form metal oxides. Potassium and sodium are soft metal which are easily cut exposing a shiny surface which changes to dull rapidly. The change from shiny to dull ...

A small piece of sodium metal is placed in a flask of chlorine gas. A little water helps expose the sodium so it can react with the chlorine gas. The reaction releases a lot of heat as the ionic ...