3.1.2 Group 2

Question 1

Group 2 elements lose __ electrons from the ___ subshell to form ___ cations

Answer 1

2 electrons, s2, 2+

Question 2

What is the 1st ionisation energy trend down group 2? Why? Protons?

Answer 2

Decreases:
- More shells –> shielding
- Atomic radius
There are more protons but shielding cancels out the effect of nuclear charge

Question 3

What is the reactivity trend down group2 ? Why?

Answer 3

Increases:

• More shells –> shielding
• Atomic radius

Question 4

How do the group 2 metals react with water? Exception?

Answer 4

Metal + water –> metal hydroxides (bases) + hydrogen gas

- Mg reacts slowly with water, faster with steam; forms Magnesium Oxide not hydroxide

Question 5

How do the group 2 metals react with oxygen? What type of reaction is this?

Answer 5

Group 2 elements + oxygen –> metal oxides

Redox

Question 6

What is the appearance of group 2 metal oxides?

Answer 6

White solids

Question 7

How do group 2 oxides react with water? Exception?

Answer 7

• Form hydroxide; OH- dissociates = alkaline solution

- Mg: reacts slowly, little dissociation = very weak alkaline solution

Question 8

The more soluble the group 2 ___, the more ____ the solution is as more OH- groups dissociate

Answer 8

hydroxide, alkaline

Question 9

How does group 2 oxides and hydroxides react with dilute acid? Type of reaction?

Answer 9

Group 2 oxide/ hydroxide + acid –> salt + water

Neutralisation

Question 10

Real world uses for group 2 oxides/ hydroxides?

Answer 10

1. Calcium hydroxide is used to neutralise acidic soils

2. Magnesium hydroxide is used to neutralise excess stomach acid