Group I Properties | Chemistry for GCSE/IGCSE - Class 10 PDF Download

The Group I metals 

• The Group I metals are also called the alkali metals as they form alkaline solutions with high pH values when reacted with water
• Group I metals are lithium, sodium, potassium, rubidium, caesium, and francium
• They all contain just one electron in their outer shell

 Physical properties of the Group I metals 

• Group I metals exhibit softness and are easily cut, with their softness and density increasing further down the group (though exceptions like sodium and potassium exist regarding density).
• Freshly cut surfaces of Group I metals display shiny, silvery appearances.
• They possess the ability to conduct both heat and electricity.
• Group I metals generally have low melting points and densities compared to other metals, with their melting points decreasing as one moves down the group; some may even melt under hot conditions.

The alkali metals lie on the far left-hand side of the Periodic Table:

Chemical properties of the Group I metals

• Group I metals exhibit high reactivity with both oxygen and water vapor in the air, necessitating their storage under oil to prevent reactions.
• When exposed to water, Group I metals undergo vigorous reactions, yielding alkaline metal hydroxide solutions along with hydrogen gas.
• The reactivity of Group I metals increases progressively as one moves down the group, prompting restrictions in schools where only the first three metals are permitted for demonstrations.

Reactions of the Group I metals with water: 

Predicting the Properties of Group I Elements

• Understanding how the top group I elements react helps in anticipating the behavior of elements lower in the Group I.

Properties of other Alkali Metals (Rubidium, Caesium, and Francium)

• As we move down the alkali metal group, including rubidium, caesium, and francium, their reactivity intensifies compared to lithium, sodium, and potassium.
• Among these metals, lithium is the least reactive at the top, while francium, found at the bottom, is exceptionally reactive.
• Predictions involving francium can be challenging due to its scarcity and radioactivity.
• For instance, when considering reactions with water:
• Predicting the Reaction with Water:
  

• You can also observe other properties such as boiling point, melting point, and density of Group I elements to predict whether other properties are likely to be larger or smaller descending down the group.
• Consider examining boiling point, melting point, and density of Group I elements to anticipate the variations in other properties as you move down the group.