topic 4 - periodic table Flashcards

1
Q

group two elements reaction with oxygen

A

rigerous reactions
need heat
get more reactive as you go down
2M(s) + O2(g) –> 2MO(s)

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2
Q

group two elements reaction with chlorine

A

more vigorous down the group
M(s) + Cl2(g)–>MCl2(s)

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3
Q

group two elements reaction with water

A

magnesium dosent react very visibly or fast
M(s) + 2H2O(l) –> M(OH)2(s) + H2(g)

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4
Q

magnesium in steam

A

magnesium reacts vigorously in steam a rapid and visible reaction
you can test the product by testing for hydrogen at the top of the tube

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5
Q

reaction of the oxides of water

A

react with water to form alkalis
form colourless solutions
MO(s) + H2O(l) –> M(OH)(aq)

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6
Q

trends in solubility of the hydroxides

A

increases down the group

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7
Q

milk of magnesia

A

magnesium hydroxide in water
indegestion remedy
neutrilises some of our stomach acid

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8
Q

reaction with acid group 2

A

neutrilisation reactions
form salts and water
eg. Mgo + H2SO4 –> MgSO4 + H2O

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9
Q

trends in solubility of the sulfates 2

A

decreases down the group

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10
Q

test for sulphate ions

A

add barium chloride or nitride solution
white precipitate will be formed
dilut nitric acid or hydrochloric acid is added

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11
Q

thermal stability

A

how stable a compound is when heated

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12
Q

factors affecting thermal stability

A

charge
ionic radius
complex ions

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13
Q

trend in boiling temperatures group 7

A

increase down the group
as london forces increase in strength
as there is an increase in number of electrons/size
so more energy needed to overcome the forces

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14
Q

thermal stability of nitrates

A

brown fumes- decomposition
nitrogen dioxie and oxygen
no brown fumes - lesser decomposition
just oxygen
all group 2 undergo decomposition
only lithium does in group 1
the rest undergo lesser decomposition

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15
Q

thermal stability of carbonates

A

group two and group one behave differently

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16
Q

flame test colours
lithium
sodium
potassium
calcium
barium

A

l- red
s- yellow
p- lilac
c- brick red
b- green

17
Q

what causes flame test colours?

A

electrons absort energy and move ot higher energy levels from their ground state to an excited state
then when the electron moves back to its ground state it releases energy in the form of light energy and the specific frequency omits the colour

18
Q

test for ammonium ions

A

no colour in flame test so add
sodium hydroxide solution and warm
ammonia gas is released
test - turns damp red litmus paper blue

19
Q

whats the trend in electronegativity of the halogens

A

decreases

20
Q

whats the trend in reactivity if the halogens

A

decreases

21
Q

reaction of chlorine with water

A

disproportionation reaction
forms chlorine water
Cl2 + H2O –> HCl + HClO

22
Q

halide ion trends

A

reducing power increases
2X¯ –> X2 + 2E¯
oxidising power decreases

23
Q

how do you cary out a flame test

A

use a platnum wire
dip into concentrated hcl
dip into solid
put in roaring flame

24
Q

what changes thermal stability

A

if atomic radius increases or charge decreases the polarisation ability decreases which is the ability to distort an atom
this means the bond is weakened less
so when the atomic radius decreases and charge increases the polarisation ability increases and the bond is weakened more making it less stable

25
Q

test for chloride, bromide and iodide ions

A

add nitric acid followed by silver nitrate
cl- white
br- cream
io-yellow
additional tests is to use ammonium solution
first dilute
cl-colourless
br-no change
io-no change
then concentrated
cl- colourless
br- colourless
io- no change

26
Q

rules for reactions of group 7 and 1+2

A

most vigerous between bottom of 1+2 and top of 7
products are salts (usualy white)
involve electron transfer to the halogen
redox reaction where the halogen is the oxidising agent
halogen goes from 0 to -1 and 1+2 go from o to either +1 or +2

27
Q

reactions between halogens

A

more reactive displaces less reactive
chlorine- stays green
bromine- goes a bit darker
iodine- goes purple
then add cyclohexane as it splits the layers

28
Q

test for thermal stability of the nitrates

A

heat and time taken for brown fumes to form
same heat
same amount
in fume cupboard

29
Q

sodium hydroxide to test for metal cations

A

disolve sample in distiled water
add few drops of dilute NaOH
continue adding and gently shake

30
Q

sodium hydroxide
copper
iron 2
iron 3
chromium
aliminum
calcium
zinc

A

Cu - light blue
i 2 - green - brown
i 3 - red - brown
cr- green
al - white - colourless
ca - white
zi - white - colourless

31
Q

acidified silver nitrate

A

to remove hydroxide ions
acidified by nitric acid so the metal anion does not form a precipitate with silver ion