The Periodic Table: Group 1

The Periodic Table: Group 1

Group 1: The Alkali Metals

General Properties

• Are elements located in the first column of the Periodic Table.
• Have one electron in their outer energy level, making them very reactive.
• Exist as metals that tend to be soft and can be easily cut with a knife.
• Are good conductors of electricity and heat due their delocalised electrons.

Reactivity

• Increases down the group due to increase in atomic size; outermost electron is further from nucleus and thus easily lost.
• React by losing their single outer electron to form a positive ion.
• Readily react with non-metals to fill their electron shells.

Physical Properties

• Density and boiling points increase down the group.
• Generally lower densities than other metals; Lithium, Sodium, and Potassium are less dense than water.
• Colours vary in the group: e.g. Lithium (silver), Potassium (silvery-white).

Chemical Properties

• React vigorously with water, forming a hydroxide and releasing hydrogen gas.
• Combustion in oxygen is common. The nature of the oxide formed varies with the individual element’s activity.

Examples of Reactions

• Sodium in water equation: 2Na(s) + 2H2O(l) -> 2NaOH(aq) + H2(g)
• Lithium in oxygen equation: 4Li(s) + O2(g) -> 2Li2O(s)

Uses of Alkali Metals

• Sodium and Potassium ions are crucial for nerve function.
• Lithium is used in rechargeable batteries for electronic devices.