Chapter 8

Question 1

What is the reactivity down group 2? How does it compare to the reactivity of group 1?

Answer 1

Reactivity increases:
- easier to lose 2 outer electrons due to increasing atomic radius and more electromagnetic shielding = decreasing ionisation energy
Same as group 1

Question 2

What is an oxidising agent?

Answer 2

Causes another species to be oxidised (it itself gets reduced)

Question 3

What is a reducing agent?

Answer 3

Causes another species to be reduced (it itself gets oxidised)

Question 4

Are group 2 elements reducing agent or oxidising agent?

Answer 4

They lose 2 electrons so are oxidised = reducing agents

Question 5

Why do melting points decrease down group 2?

Answer 5

• atomic radius increases down the group = weaker forces of attraction between the positive ions and delocalised electrons
• requires less energy to break = decreasing melting points

Question 6

Which element’s melting point is an exception?

Answer 6

Magnesium as it’s lower than expected

Question 7

Which redox reactions do group 2 elements occur in?

Answer 7

Metal + oxygen -> metal oxide
Metal + water -> metal hydroxide + hydrogen
Metal + acid -> salt + hydrogen

Question 8

How can you check if something. Is a redox reaction?

Answer 8

Check the ionisation energies
See if one element is oxidised and one is reduced

Question 9

What happens when oxides of group 2 elements react with water?

Answer 9

Hydroxide ions are released and form alkaline solutions of the metal hydroxides
Group 2 hydroxides are only slightly soluble in water