Group 2,7 Flashcards
Describe what happens to the atomic radius as you go down group 2
Increases, because there are more electron shells
Describe what happens to the ionisation energy as you go down group 2
Decreases, because the atomic radius increases, because there are more electron shells, so there is a greater distance between the outer electron and nucleus, so there is a weaker attraction, so less energy is required to overcome these forces of attraction and remove an electron.
Describe what happens to the melting point as you go down group 2
Decreases, because the ionic radius increases, so there is a greater distance between the delocalised electrons and nucleus, so the strength of the metallic bonds decreases
Which element in group 2 deviates the trend in melting point
Magnesium
Magnesium can be used to extract titanium from its ore.
TiO2 (s) + 2Cl2 (g) + 2C (s) → TiCl4 (1) + 2CO (g)
TiCl4 (l) + 2Mg (s) → Ti (s) + 2MgCl2 (s)
Describe the use of calcium compounds
Calcium compounds can be used to remove the sulfur dioxide that is released in fossil fuel emission, before it turns into acid rain.
CaCO3 (s) + SO2 (g) → CaSO3 (s) + CO2 (g)
How are hydroxides formed
When Group2elements react with water
What happens to the solubility of Group2hydroxides as you go down the group
The solubility of Group2hydroxides increases as we go down the group.
Magnesium reacts with water
Mg (s) + 2H2O (1) → Mg(OH), (aq) + H2 (g)
Magnesium reacts with steam
Mg (s) + H2O (g) → MgO (s) + H2(g)
Describe the use of magnesium hydroxide
Magnesium hydroxide is often used to cure acid reflux, or heartburn.
Explain why magnesium hydroxide is effective
it’s a strong enough base to neutralise the excess stomach acid, but not strong enough to cause any damage to the body.
Describe what happens to the solubility of group 2 sulfates as you go down the group
Decreases
Describe the use of barium sulfate
Barium meal in x-rays
State basic properties of group 7 elements
- Very reactive non-metals
- Diatomic
- Halogens
What do halogens form when they gain an electron
Halides
Describe Flourine at room temperature
Pale yellow gas
Describe Chlorine at room temperature
Greenish gas
Describe bromine at room temperature
Brown liquid
Describe iodine at room temperature
Dark grey solid
Describe the trend in electronegativity as you go down group 7
Decreases
Describe the trend in melting/boiling point as you go down group 7
Increases, elements have more electrons, stronger Van der Waals forces, requires a great deal of energy to overcome
Describe the trend in oxidising power of halogens as you go down group 7
Decreases
Describe the trend in reducing power of halides as you go down the group
Increases
