Group 1 Reactions with Water

IGCSE Edexcel Chemistry
2.1 Group 1 reactions with water
Key Concept: Alkali metals react with water to produce a metal hydroxide and hydrogen gas. Similar reactions show they are a family of elements.

Section A: Observations and Equations

1. Name three Group 1 metals. [1]
2. State two observations when sodium reacts with water. [2]
3. Write the word equation for alkali metal + water. [1]
4. Write balanced symbol equations for lithium and sodium reacting with water. [2]
5. What gas is produced, and how would you test for it? [2]

Section B: Evidence of a Family

6. Explain how similar reactions with water provide evidence that Group 1 is a family of elements. [2]
7. Explain why Group 1 metals form +1 ions in reactions. [2]
8. Predict the products when potassium reacts with water (name and formula). [2]

Section C: Safety

9. Explain why alkali metals are stored under oil. [2]

Total marks: 14

Mark Scheme

1. Any three: lithium, sodium, potassium, rubidium, caesium [1]
2. Any two: floats, fizzes, moves on surface, melts to a ball, heat produced, hydrogen released [2]
3. Alkali metal + water -> metal hydroxide + hydrogen [1]
4. 2Li + 2H2O -> 2LiOH + H2; 2Na + 2H2O -> 2NaOH + H2 [2]
5. Hydrogen; lit splint gives a squeaky pop [2]
6. They react in the same way with water, producing hydrogen and hydroxide; similar properties indicate a group/family [2]
7. One electron in outer shell; they lose one electron to form +1 ions [2]
8. Potassium hydroxide (KOH) and hydrogen (H2) [2]
9. Prevents reaction with air/moisture or water; reduces risk of oxidation and fire [2]