Chapter 9 - Group 2 Flashcards
what are group 2 elements called
alkaline earth metals
what is the charge of a group 2 element ion
2+ always
what block are g2 elements in, and what is the significance
s block. this means that the highest energy electron will be found in an s orbital. specifically it will be in s2
how does the melting point change down group 2 and why
is there an anomaly to this trend
it decreases
because down the group the atomic radius increases because the shielding increases, which means that the delocalised elections experience less attraction to the metal cations
magnesium doesnt follow this trend
how does reactivity change down g2
reactivity increases
because the atomic radius increases because the shielding increases hence the highest energy electron experiences a lower attraction to the nucleus as it is further away so less energy needs to be supplied to remove the electrons needed to form a 2+ ion and it is easier to react
why is magnesium reacted with steam and not water
because the reaction with water is very slow because magnesium requires a lot of energy to react which needs to be supplied with the temperature of the steam
what are the products when g2 elemtns readt with water
a metal hydroxide and hydrogen gas
X(OH)2 +H2
what are the products when g2 elemtns readt with steam
a metal oxide and hydrogen
XO + H2
how can magnesium be usd to extract titanium give the equations
TiO2(s) + 2Cl2(g) + 2C(s) —–> TiCl4(l) + 2CO2(G)
TiCl4(L) + 2Mg(s) —-> Ti(s) + 2MgCl2(s)
hwo does the sulability of grup 2 hydroxides change down the group
it increases
hwo does the sulability of grup 2 sulfates change down the group
it decreases
give equations for how sulfur oxide reacts to form sulfuric acid
2SO2(g) + O2(g) —-> 2SO3(g)
SO3(g) + H2O(l) —> H2SO4(aq)
what is magnesium hydroxide called and what is it used for
milk of magnesia, used to neutalise stomach acid and cure acid reflux or heartburn
why is Mg(OH)2 an effective medicine
because its a strong enough base to neutralise the acid, but its not strong enough to cause any damage, its also insoluable in water so it wont get absorbed
what is slaked lime and what are its uses
Ca(OH)2(s) its is used to treat acidic soil
what is limestone and what are its uses
CaCO3(s) used in cement, and in construction
what is quicklime and are its uses
CaO(s), used in construction and manufacturing
what is limewater and what are its uses
a saturated solution of calcium hydroxide, used to extract sugar from beets
what is barium meal and what is it used for
BaSO4(aq) it is used in x-rays to image someones digestive tract
what makes barium meal suitable for x ray imaging
it is dense enough to absorb x rays, while being insulabke enough that it wont be absorbed by the body to cause damage to cells
what is epsom salt and what is it used for
MgSO4(aq) it is used to crate magnesium in the body, and increase the water content of the body
how can we test for sulfate ions
using acidified barium chloride (BaCl2)
why must barium initially be acidified
in order to encure that there are no carbonate ions present which will also create a while precipitate with barium chloride
give the equations to test for sulfate ions
Ba(s) + 2HCl(aq) —> BaCl2(aq) + H2(g)
then
BaCl2(aq) + SO4^2-(aq) —-> BaSO4(s) + 2Cl^1-(aq)
what makes barium chloride suitable to test for sulfate ions
barium sulfate is highly insoluble so it will form a white precipitate
why can we not make acidified barium chloride with sufluric acid
because were testing for sulfate ions so the only ones present should be the ones in the sample were testing
