9 - Group 2 Alkaline Earth metals Flashcards
Explain the trend in ionisation energies of Group 2 metals. (5)
• Number of electron shells increases
• Atomic radius and electron shielding increase
• Less electrostatic attraction
• Easier to remove electrons
• Less energy required
Describe and explain the trend in atomic radius of Group 2 metals.
- Number of electron shells increase down group
- Atomic radius increases
Describe and explain the trend in melting point down Group 2 metals.
- Atomic size increases
- Metallic bonding decreases
- Distance between nuclei and delocalised electrons increases
- Electrostatic attraction decreases
- Melting point decreases
Describe the trend in reactivity down Group 2.
Increases
What is formed when Group 2 metals react with liquid water?
Metal hydroxide
Describe and give the reaction of Mg with steam.
Forms MgO (s), H2 (g)
White flame
What observations happen more down Group 2 in the reaction of Group 2 metals with water?
Fizzing
Metal dissolving
Solution heats up
Describe the trend in formation of a white ppt down Group 2 when reacting with water.
Less white ppt forms down group (form hydroxides)
Describe the process of the extraction of Ti.
TiO2 + 2Cl2 + 2C –> TiCl4 + 2CO
TiCl4 + 2Mg –> Ti + 2MgCl2
Describe the trend in solubility of Group 2 hydroxides down the group.
Increases
Describe and explain the medical use of Mg(OH)2.
- Neutralise stomach acid
- As it is insoluble in water
Describe and explain the agricultural use of Ca(OH)2.
- Neutralise acidic soil
- Partially soluble
Describe the solubility of Group 2 sulfates down the group.
Decreases
Give the solubility of barium sulfate in water.
Insoluble
Describe and explain the medical use of BaSO4.
- Given to make X-rays of patients’ intestines.
- Insoluble so is not absorbed into blood
Describe the test for sulfate ions.
Add dilute HCl
Add BaCl2
White precipitate forms of barium sulphate
Why is HCl added to BaCl2 to test for sulfates?
Reacts with carbonates that would otherwise give false white Barium Carbonate precipitates.
