Inorganic Chapter 2: Group 2 & Group 7 Flashcards
What is group 2 called?
Alkaline Earth metals
What is trend in Atomic Radius down group 2?
It increases - no. of shells increases
What is the trend in first ionisation energy down group 2?
It decreases - electrons get further away from the nucleus - easier to remove
What is the trend in reactivity down group 2?
It increases - electrons are easier to remove due to distance from nucleus
What is the trend in melting points down group 2?
Generally decreases - Metal ions get bigger, nuclei get further away from the delocalised electrons, easier to break bonds
What ions do group 2 elements form?
2+ ions
What do group 2 elements produce when reacting with water?
A metal hydroxide & Hydrogen
E.g. Ca + 2H2O -> Ca(OH) + H2
What happens to the oxidation state of group 2 elements when they react?
They are oxidised from a state of 0 to +2
What are the two factors that decrease first ionisation energy down group 2?
Increased shielding
Increased atomic radius
What do solubility trends with group 2 elements depend on?
The compound anion (OH, SO4, etc)
What is the trend down group 2 of solubility with singly charged anions?
Increases
What is the trend down group 2 of solubility with doubly charged anions?
Decreases
How can you test for sulfate ions?
Add acidified barium chloride, see a white ppt on a positive result
What are group 2 elements used for?
Neutralising acidity - often in agriculture or antacids
Magnesium is used to extract Titanium
Calcium compounds used to remove SO2
‘Barium meals’ for X-rays
How is Magnesium used to extract titanium?
It reduces the Ti
TiCl4 + 2Mg -> Ti + 2MgCl
How are calcium compounds used to remove SO2?
Flue gas desulfurisation - Mix the compound (CaO or CaCO3) with water, then sprayed it onto the flue gases.
CaO + 2H2O + SO2 -> CaSO3 + 2H2O
CaCO3 + 2H2O + SO2 -> CaSO3 + 2H2O + CO2
What is a ‘Barium meal’ and how does it work?
People eat small amount of barium sulfate, which is opaque to X-rays, and will coat the tissue of the digestive tract, showing it on X-rays to diagnose issues.
What is Group 7 called?
The Halogens
What ions do group 7 form?
1- ions