Group 1 Elements

• Group 1 elements are known as the alkali metals and they're pretty reactive
• The group 1 elements are reactive, soft metals
• The alkali metals are lithium, sodium, potassium, rubidium, caesium and francium
• All group 1 elements have 1 electron in their outer shell which makes them very reactive and give them similar properties
• The alkali metals are all soft and have low density
• Increasing reactivity - the outer electron is more likely to be lost as the attraction between the nucleus and electron decreases, because the electron is further away from the nucleus the further down the group you go
• Alkalis have lower melting and boiling points
• Alkalis have a higher relative atomic mass
• Alkali metals form ionic compounds with non-metals
• The group 1 elements don't need much energy to lose their one outer electron to form a full outer shell, so they readily form 1+ ions
• It's so easy for them to lose their outer electron that they only ever react to form ionic compounds
• These ionic compounds are generally white solids that dissolve in water to form colourless solutions
• Reaction with water - When group 1 metals are put in water, they react vigorously to produce hydrogen gas and metal hydroxides (compounds that dissolve in water to produce alkaline solutions)
• Reactions with water - The more reactive (lower down in the group) an alkali metal is, the more voilent the reaction
• Reaction with water - The amount of energy given out by the reaction increases down the group (the reaction with potassium releases enough energy to ignite hydrogen
• 2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g) (All the Group 1 metals react with water in a similar way
• Reaction with chlorine - Group 1 metals react vigorously when heated in chlorine gas to form white metal chloride salts
• Reaction with chlorine - As you go down the group, reactivity increases so the reaction with chlorine gas get more vigorous. E.g. 2Na(s) + Cl2(g) -> 2NaCl(s)

  sodium chlorine sodium chloride
• Reaction with oxygen - The Group 1 metals can react with oxygen to form a metal oxide. Different types of oxide will form depending in the Group 1 metal
• Reaction with oxygen - Lithium reacts to form lithium oxide (Li2O)
• Reaction with oxygen - Sodium reacts to form a mixture of sodium oxide (Na2O) and sodium peroxide (Na2O2)
• Reaction with oxygen - Potassium reacts to form a mixture of potassiumperoxide (K202) and potassium superoxide (KO2)
• The reactions with oxygen are why Group 1 metals tarnish in the air - the metal reacts with oxygen in the aie to form a dull metal oxide layer
• Group 1 metals have different properties to transition metals
• Group 1 metals are much more reactive than transition metals - they react more vigorously with water, oxygen or Group 7 elements, for example
• Alkalis are also much less dense, strong and hard than the transition metals, and have much lower melting points. E.g. manganese melts at 2000 °C, sodium melts at 98 °C