2.2.4 reactions of period 3 elements

Question 1

reactions of elements in period 3

Answer 1

tehya re all redix reactions

Question 2

reactions of period 3 elements and water

Answer 2

na,mg,cl - only ones that react with water

na - vigourouse - floats to the surface and fizzes rapidly
melts because of the heat energy released by the reaction
makes NaOH and H2

mg - slow at room telp
producut is less alkaline becuase it is sparingly soluable
makes mg(OH)2 +H2
faster when heated with steam
mg(s) +H2O -> MgO +H2

Question 3

period 3 element reaction with water

Answer 3

mg
makes MgO
flame is verry intense

Al
burns brightly
gives aluminum oxide which is a white powder
appears unreactive - as coated in oxide which prevents further reaction
makes Al2O3

silicon
has to be heated
SiO

phsophoris
makes
P4O10 g
in limited suppluy of o2 p2o3 can be formed

red phosphorus - heated befor reacts
white phosphorus - spontaneously ignites with air - white smoke of phosphorus pentoxide is gieven of

sulfur
burns blue flame to produce colourless ags - sulfur dioxide
a little sulfur trioxide also formed
s02

Question 4

oxides of elements in period 3

Answer 4

metal oxides
giant ionic lattice
high mp
aluminum oxide special

non metal oxides
silcon dioxide - macromolecular
highmp

phosphorus and silfur = moleculcular
why s oxides are gass
p4o10 is higher as larger molecule

Question 5

aluminium oxide

Answer 5

ionic sioteh some covalent character
small positive charge can get close and distort the o2- electron cloud = covalent character

ionic character can be predicted by the diffrence in electronegativities

Question 6

basic oxides of period 3

Answer 6

metals na and mg
sodium
reacts ith water to give naOh - strongly allaline pH 14

magensium
reacts with water to give partially alkaline
as mgO is sparingly soluable
pH 9

Question 7

insoluable period 3 oxides

Answer 7

aluminum oxide
isolable in H2O - as the ionic bonds are to strong (partially to do with the covalent character)

silicon dioxide
insoluable in water - macromolecular

Question 8

acidic oxides of period 3

Answer 8

non metals
phosphorous pentoxide
reacts violently to give phsophoric v oxide taht ionises into phsophoric acid
h3po4
faily strong acid

sulfur dioxide
fairly soluable reacts to gibe sulurouse acid h2SO3
partiall dissociates

sulfur trioxide
fully disocciates
H2SO4
sulfiric acid

Question 9

aicic basic reactions of period 3 oxides

Answer 9

na and mg react with acid to give a salt and water

al - amphoteric - reacts as both an acid and an alkali - either ends up with a metal or as a metal in the salt
eg
reacts with base to form naAl(OH)4- sodium alluminate

si - weak acid with a strong base
eg reacts with naOH to give Na2SiO3

p - happens in 3 stages as has 3 H to react with an Oh
phosphoric acid is involved as water

sulfur dioxide
reaction with a base
1. forms sodium hydrogen sulphate -NaHSO3
2. looses the proton to make Na2SO3 and water when reacts again with NaOH