Family
Alkali metal
Group 1 metals (excluding hydrogen). One loosely held — extremely reactive, especially with water.
Worth knowing
- Lose one electron to form +1 .
- Reactivity increases down the group: Li → Na → K → Rb → Cs.
- Soft enough to cut with a knife. Stored under oil so they do not react with air or moisture.
- Sodium and potassium are essential for nerve signaling.
Examples