Alkali Metals

The name alkali comes from the Arabic al-qaliy, meaning "the plant ashes" -- the original source from which alkaline substances were obtained. A water extract of burnt plant ash, called potash, contains mainly potassium carbonate, K₂CO₃.

The alkali metal group (Group 1) consists of six elements: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). All six are metals that are:

• generally soft (can be cut with a knife) and
• highly reactive. …