Alkali metals are a group of chemical elements found in Group 1 of the periodic table. They include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These elements share similar properties because they each have one electron in their outermost shell, which they readily lose to form positively charged ions (+1 charge).
Key characteristics of alkali metals:
- Highly reactive: They react quickly with water, oxygen, and halogens.
- Soft metals: They can be cut easily with a knife.
- Low density: Lithium, sodium, and potassium are less dense than water.
- Shiny appearance: Freshly cut alkali metals have a silvery luster, but they tarnish quickly in air.
- Conductors of heat and electricity: Like most metals, they allow electricity and heat to pass through them easily.
- Form strong bases: When they react with water, they produce hydroxides (alkalis) and hydrogen gas. For example, sodium reacts with water to form sodium hydroxide (NaOH).
Because of their high reactivity, alkali metals are usually stored in oil to prevent contact with air or moisture.