group 2 Flashcards
Why are group two elements reducing agents And are oxidised
They add electrons to other species
Mg + 2HCl -> MgCl2 + H2
identify changes in oxidation numbers and state what is being oxidised and reduced
Mg 0 to 2+ oxidised
H +1 to 0 reduced
why do group two elements become more reactive down the group
The total energy needed to react decreases as nuclear attraction on the outer shell decreases As first ionisation energy decreases because of increasing atomic radius and shielding so electron becomes easy to remove and react
beryllium doesn’t even react
Magnesium reacts slowly
Calcium and barium react normally
What would be produced if a group two metal is added to oxygen
metal oxide.
What would be produced if a group 2 oxide is added to water
metal hydroxide and hydrogen
state and explained the trend in alkalinity of the solution formed when group two oxides are added to water
Group two oxides react with water to form metal hydroxide, Hydroxide ions cause alkalinity, Down the group solubility of the metal hydroxide increases therefore increasing the pH and alkalinity of solution
what happens to first ionisation energy down group 2 and why
As we move down the group, atomic radius and ionic radius increases because number of shells increase therefore shielding also increases so first ionisation energy decreases despite nuclear charge increasing
do melting and boiling points increase or decrease down group 2 and why
Melting and boiling points generally decrease due to ionic radius increasing so force between central ion and surrounding electrons is decreased
However there is an exception for magnesium which is lower than usual
what does a group two metal and oxygen make
Group 2 metal oxide
what does a group two metal and water make
Group 2 metal hydroxide and hydrogen
what does a group 2 metal and acid make
Salt and hydrogen
Does group 2 metal hydroxides Solubility in water increase or decrease down the group
Increases and forms of white precipitate
Does solubility of group 2 metal sulphate decrease or increase down the group
Decreases
What does group two metal oxides and water make
Hydroxide which causes alkalinity
What is the use of a barium sulphate
barium sulphate is insoluble this is used in medicine, it coats the inner tissue showing the structure of organs on an X ray without being dissolved in the blood
What is barium chloride used for
In the sulphate test to form a white precipitate
What is used to reduce constipation/indigestion and why
Magnesium hydroxide and barium sulphate Because they are suspensions
What is magnesium used for
It’s oxidised to extract titanium from titanium chloride
What is calcium hydroxide used for
to neutralise acidic soil
