Group 2 Flashcards
What is atomic radius? and what is the trend?
Measure of size of an atom
and size of an atom increases down a group
e.g calcium is bigger than magnesium
thats bcs the outer electrons are in a new shell which is further away from the nucleus
What is first ionisation energy?
First ionisation energy decreases down a group
thats bcs e.g Mg and Ca
Mg has 2 full shell and 3rd shell which has 2 more electrons
whereas Ca has 3 full shells with so the 4th shell is further away from the nucleus & more shielding occurs
so the 4th shell electrons experience weaker attraction to nucleus
so it’s easier to remove electron at ca
so calcium has lower first ionisation energy
first ionisation energy decreases down a group
Group 2 elements are all…
alkali earth metals so they bond metallically
All alkaline earth metals are …
solid at room temperatures
Bigger a metals cation…
the lower the melting point
Down group 2 , the cations in metallic lattice
get larger so there is a greater distance between the delocalised electron and the nuclei so there’s a weaker attraction between the delocalised electrons and cation
melting point decreases down group 2
so as we go down group 2 metallic bonding gets weaker
the weaker melting point decreases
What element doesn’t follow the trend of as we go down a group melting point decreases
Magnesium as it’s melting point it’s way lower than all group 2 elements
What is Magnesium used for?
to extract titanium
Separating a metal from its ore is called
extraction
How’s a metal usually used to extract?
They use carbon to react it to extract titanium
e.g by heating iron dioxide with carbon producing iron and carbon dioxide
What happens if we extract titanium with carbon?
if we use titanium oxide with carbon we get titanium carbide and oxygen
which is brittle and makes the metal useless material
so we need another way
How is titanium extracted using magnesium’s
it’s a 2 stage process
where titanium oxide is first heated with carbon and chlorine producing titanium chloride and then magnesium is used to form Titanium and magnesium chloride
in this reaction magnesium donates electrons to titanium so it’s acting as a reducing agent
bcs it’s extracted in 2 stages it’s less efficient then others which is extracted in a continues process
but titanium strength low density and high melting point makes it worth to
Burning fossil fuels like coal produces
sulfure dioxide which is let into the atmosphere which reacts with oxygen to form sulfur trioxide
which has the equation
2SO2 (g) + O2 (g) —> 2SO3 (g)
sulfur trioxide reacts water in clouds to form sulfuric acid
SO3 (g) + H2O (l) —> H2SO4 (aq)
which causes acid rain
How do we stop sulfur dioxide from entering the atmosphere
Calcium provides a way
we get Calcium oxide also known as (quicklime) and mix it with water and produces a mixture called slurry
this slurry is sprayed over the sulfur dioxide gas in a special designed gas which forms calcium sulfide and water
bcs this CaSO3 is a solid it can be dried and collected safely
quicklime is readily available
process is used also to react
calcium carbonate ?known as lime stone
and mix it with water to form a slurry and spray it over the sulfur dioxide and collect the calcium sulfide
this method is known as wet scrubbing
it reduces acid rain by 98%
what do we use to prevent acid rain
burning fossil fuels gives off sulfur dioxide which causes acid rain
we can prevent this by spraying slurry of calcium oxide or calcium decarbonise over the sulfuric dioxide gas and collect the calcium sulfide that forms
Calcium and water react to form
calcium hydroxide and hydrogen
