Section 2 - Group 2 and Group 7 Elements Flashcards
What type of ions do group 2 metals form?
2+ ions.
What is the trend in atomic radius down group 2 and why?
Increases - extra electron shells are added.
What is the trend in First Ionisation Energy down group 2 and why?
Decreases because…
- electron shells increase
- shielding occurs
- electrons are futher from nucleus
What is the trend in reactivity down group 2 and why?
Increases because…
- First IE decreases
- Easier to lose electrons
What is the trend in mpts down group 2 and why?
Decreases…
- they have metallic structures
- metal ions get bigger but no. of electrons stays the same
- larger ionic radius means the electrons are further from the nuclei
What are group 2 elements reduced or oxidised when reacted?
Oxidised
What is the trend in solubility when reacting Mg, Ca, Sr and Ba with OH-?
Increases
What is the trend in solubility when reacting Mg, Ca, Sr and Ba with SO42-?
Decreases.
What is the solubility of Mg(OH)2?
Sparingly soluble
What is the solubility of BaSO4?
Insoluble
What is the test for sulfate ions?
Add acidified barium chloride to a solution containing sulfate ions and a white precipitate of barium sulfate will form.
Why must you acididfy the solution in the sulfate ions test?
To get rid of lurking sulfites or carbonates which would also produce a white precipitate
What can be used to neutralise acid soils?
Calcium hydroxide (Ca(OH)2)
What can be used to neutralise excess stomach acid?
Magnesium hydroxide (Mg(OH)2)
Give the ionic equation for neutralisation:
H+(aq) + OH-(aq) —> H2O(l)
Explain the barium meal:
- a patient swallows a suspension of barium sulfate
- it coats their tissues
- it is opaque to x-rays so the tissues are visible
Explain how magnesium can be used to extract titanium from its ore and give the equation:
TiCl4(g) + Mg2(g) —> Ti(s) + 2MgCl(l)
- TiO2 (the main titanium ore) is converted to titanium chloride (TiCl4) by heating it with carbom in a stream of chlorine gas
- the titanium chloride is then purified by fractional distillation
- it is reduced by Mg in a furnace at almost 1000oC
Explain how calcium oxide and calcium carbonate can be used to remove sulfur dioxide and give the equations:
CaO(s) + 2H2O(l) + SO2(g) —> CaSO3(s) + 2H2O(l)
CaCO3(s) + 2H2O(l) + SO2(g) > CaCO3(s) + 2H2O(l) + CO2(g)
- powdered calcium oxide (CaO) and calcium carbonate (CaCO3)
- a slurry is made by mixing these with water
- it’s sprayed onto the flue gases
- a solid waste product of calcium sulfite is formed
What is the trend in electronegativity down group 7?
Decreases…
- electrons are further from the nucleus
- outer electrons are shielded by inner electrons
What is the trend in bpts down group 7?
Increases…
- relative mass increases
- strength of Van der Waals increases
What colour is F2?
Pale yellow
What state is F2?
Gas