The Periodic Table: Group 1 - Alkali Metals
The Periodic Table: Group 1 - Alkali Metals
- Group 1 of the Periodic Table is known as alkali metals. Members include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr).
- Alkali metals have only one electron in their outer shell, this makes them highly reactive. Because these metals want to achieve a stable electron configuration, they readily donate their outer electron during chemical reactions.
- The reactivity of alkali metals increases down the group. This is because the outer electron is more easily lost as it gets further from the nucleus.
- All alkali metals are soft and have low densities. Lithium, Sodium and Potassium are less dense than water.
- Alkali metals have low melting and boiling points compared to most other metals. These decrease on going down the group.
- Alkali metals react vigorously with water to form an alkali (a soluble base) and hydrogen gas. This reaction again becomes more violent down the group. As an example, the reaction of sodium with water will be: 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g).
- Because of their high reactivity, alkali metals are never found in their elemental form in nature. They are always found as compounds.
- When an alkali metal reacts with a halogen (Group 7 elements), it forms a salt. For instance, sodium reacts with chlorine to form the salt, sodium chloride (table salt).
- The alkali metals, particularly sodium (Na) and potassium (K), play essential roles in living organisms. For instance, they are involved in nerve transmission and the regulation of blood pressure.
- It’s essential to handle these metals with care due to their high reactivity. They are usually stored in oil to prevent reaction with air and moisture.
Remember to review the patterns and trends in properties in Group 1 elements, as well as the chemical reactions they undergo. This includes reactions with water, oxygen and halogens, and understanding these reactions can provide you with a deeper understanding of these very reactive metals.