Group 1 Alkali Metals List
- Lithium
- Sodium
- Potassium
Group 1 Alkali Metals Properties
Melting Point
The melting point of group 1 alkali metals decreases as you move down the group.
Reactivity with Cold Water
- They effervesce
- They turn green universal indicator purple
- They float
- They disappear
- They react in the following way:
- Lithium: 2 Li(s) + 2H₂O(l) → 2 LiOH(aq) + H₂(g)
- Sodium: 2 Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)
- Potassium: 2K (s) + 2H₂O (l) → 2KOH (aq)
Boiling Point
The boiling point of group 1 alkali metals decreases from lithium to potassium.
Properties of Group 1 Compounds
- All are metals
- They react rapidly with oxygen to form metal oxides
- React with water to form metal hydroxides and hydrogen
- Reactivity increases going down the group
- They have oxides which react with water to form a soluble alkaline hydroxide
- They have white compounds which dissolve to produce colorless solutions
Reactivity in Water
Reactivity increases down the group and all group 1 elements float in water.
Chemical Equations of Alkali Metals
Reaction with Oxygen
- Lithium: 4 Li (s) + 02 (g) → 2Li₂O (s)
- Sodium: 2 Na (s) + 02 (g) → 2Na₂O (s)
- Potassium: 4 K(s) + 02 (g) → 2K₂O (s)
Reaction with Water
The oxides and hydroxides of the alkali metals are alkaline. They react with water to form hydroxides:
- Na₂O(s) + H₂O(l) → 2NaOH(aq)
Alkaline Earth Metals (Group 2 Elements)
As group 1 descends, the atoms increase in radius. The outer negative electron becomes further from the positive nucleus and is shielded more by the inner electron. This means the outermost electron is attracted less strongly to the nucleus and is lost more easily.
Safety Precautions
- Store in oil to prevent contact with water and oxygen
- Do not touch them - use tweezers
- Wear a lab coat and goggles
- Keep away from flames and water
- Dab off oil before use
