Group 2 Alkaline Metals Flashcards
(33 cards)
What is the trend in atomic radius
Increases down group due to more electron shells
What the trend in 1st ionisation energy
Decreases down the group as shielding and atomic radius increases, so electrostatic force of attraction between outer electrons and nucleus is weaker as distance is greater
What’s the trend in reactivity
Reactivity increases done group as electron is more easily lost due to larger atomic radius and increased shielding
What’s the trend in melting point
Melting point decreases down group as metallic bonding weakens as atomic size increases, as distance between +ve ions and delocalised electrons increases, so force of attrition is weaker and requires less energy to break
How do group 2 metals react with oxygen
They burn in oxygen
What does the reaction between metal and water produce
Metal hydroxide and hydrogen
What 4 observations are made when group 2 metals react with water
- fizzing
- metal dissolving
- solution heating up
- with calcium, a white precipitate forming (less precipitate forms down group)
Why is titanium a useful metal
It’s abundant, low density and corrosion resistant
Why is titanium used for
Strong, light allows used in aircrafts
Describe the 1st step in extraction titanium
TiO2 (s) in converted into TiCL4 (l) by heating at 900 degrees Celsius, with carbon and chlorine gas
Give the equation in the 1st step of extracting titanium
TIO2 + 2C + 2CL2 —> TICL4 + 2CO
Describe the 2nd step of extracting titanium
TICL4 is purified by fractional distillation in an argon atmosphere
Describe step 3 in extracting titanium
TICL4 is reduced by magnesium at 500 degress celcius in an argon atmosphere
Why is TiO2 converted into TICL4
TICL4 is molecular, so liquid at room temp, so can be purified by fractional distillation
Whereas as TIO2 is ionic so solid at room temp
Give 4 reasons for the high cost of extracting titanium
- expensive cost of magnesium
- batch process so is slower
- argon expenses and needs to remove moisture
- high temperatures required
What can calcium sulfite be used for
Making calcium sulphate for plasterboard
What is the trend in solubility of hydroxides
Solubility of hydroxides increases down group
Explain a use of magnesium hydroxide
Used in medicine to neutralise excess stomach acid and treat constipation
Why is magnesium hydroxide used instead of calcium carbonate in medicine
Calcium carbonate produces carbon dioxide gas
Give a use of calcium hydroxide
Used in agriculture to treat acidic soils
Why is a suspension of calcium hydroxide in water more alkaline than magnesium hydroxide
Calcium hydroxide is more soluble so more hydroxide ions present in solution
What is lime water
Aqueous calcium hydroxide
Give the equation for lime water reacting with CO2
Ca(OH)2 + CO2 —> CaCO3 + H2O
Why does limewater turn cloudy when reacting with carbon dioxide
Calcium carbonate is produced
