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A-level Chemistry > Periodic Table And Such > Flashcards

Periodic Table And Such Flashcards

1
Q

Atomic radius down group 2

A

Increase
(More shells)

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2
Q

Ionisation energy down group 2

A

Decrease
(More shells = more distance = less effective nuclear charge = less energy required)

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3
Q

Electronegativity down group 2

A

Decreases
(More shells = more shielding and more distance = less effective nuclear charge = less electronegative)

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4
Q

GROUP 2
Reactions with water

A

BERYLLIUM
Reacts with steam at high temps (but basically doesn’t react)
MAGNESIUM
Burns in steam; slight reaction with cold water but forms magnesium hydroxide layer which is insoluble and acts as barrier and also hydrogen
CALCIUM STRONTIUM BARIUM
All react with water with increasing vigour to make (group 2) hydroxide and hydrogen

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5
Q

GROUP 2
Reactions with Oxygen

A

BERYLLIUM
Burns (when powdered)
ALL OTHERS
Burn to make metal oxide

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6
Q

GROUP 2
Reactions with (dilute) HCl (hydrochloric acid)

A

All react to form metal chloride and H2 gas
Reactions get more vigorous down the group

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7
Q

GROUP 2
Reactions with (dilute) sulphuric acid

A

BERYLLIUM AND MAGNESIUM
Similar to HCl; react to form metal sulphate and H2 gas
CALCIUM STRONTIUM BARIUM
Form insoluble/ partially insoluble metal sulphates so layer of insoluble sulphate forms

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8
Q

GROUP 2
Reaction with nitric acid

A

BERYLLIUM
Can’t tell. Beryllium is Quirky and scientists can’t agree about it
ALL OTHERS
Produce hydrogen gas and metal nitrate

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9
Q

GROUP 2 HYDROXIDES SOLUBILITY

A

Increase as you go down the group
Larger ionic radius for same ionic charge so charge density decreases so less energy required for lattice dissociation (breaking bonds)
Same hydration enthalpy (forming bonds)
Breaking bonds releases more energy than forming them so more likely to dissolve.
MAGNESIUM: insoluble
CALCIUM: slightly soluble
STRONTIUM AND BARIUM: Soluble

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10
Q

GROUP 2 SULPHATES SOLUBILITY

A

Decrease down group
Lattice dissociation enthalpy is relatively constant down the group but hydration enthalpy decreases
So less likely to dissolve and form new bonds with water molecules
MAGNESIUM AND CALCIUM: Soluble
STRONTIUM: insoluble
BARIUM: insoluble

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11
Q

GROUP 2 CARBONATES SOLUBILITY

A

Decreases down group
Basically insoluble

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12
Q

GROUP 2 CARBONATES THERMAL STABILITY

A

More stable down the group
More shells = less charge dense = less polarising = more stable
Decompose to form group 2 oxide and CO2

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13
Q

GROUP 2 NITRATES THERMAL STABILITY

A

Thermal stability increases down group
More shells = less charge dense = less polarising = more stable
Decompose to form group 2 oxide and nitrogen dioxide and oxygen

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14
Q

Atomic radius down group 7

A

Increase
(More shells)

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15
Q

Electronegativity down group 7

A

Decrease
(Charge density and electron shielding decrease with more shells)

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16
Q

Melting and boiling temperatures down group 7

A

More electrons as you go down
London forces increase
So harder to separate
So melting point and boiling point increase

17
Q

Oxidising power down group 7

A

OIL
F doesn’t lose any
So oxidising power decreases down group

18
Q

GROUP 7 REACTION WITH HYDROGEN

A

All make hydrogen halide (HX)
FLUORINE
Explosive explosive
CHLORINE
Explosive exposed to sunlight or flame- makes
BROMINE
Mild explosion in flame
IODINE
Only combine partially even under constant heat (reversible reaction, too)

19
Q

GROUP 7 REACTION WITH PHOSPHORUS

A

ALL halogens react with phosphorous to form trihalides (phosphorus (|||) halides)
EXCESS CHLORINE OR BROMINE forms pentahalides (phosphorus (V) halides)

20
Q

GROUP 7 REACTIONS WITH SODIUM

A

ALL react to produce sodium halides

21
Q

GROUP 7 REACTIONS WITH IRON

A

IRON burns in ALL HALOGEN GASES (except iodine) to give iron (|||) halides
IODINE: only produces iron (||) iodide

22
Q

GROUP 7 REACTIONS with iron (||) ions

A

FLUORINE: it’s solution. Won’t work with fluorine, it just reacts with the water
CHLORINE AND BROMINE: oxidise iron (||) to iron (|||) ions. Cl and Br are reduced in the process.
IODINE (in iron (|||)): weak. It is oxidised. (Iron (|||) => Iron (||), and I- => I)

23
Q

GROUP 7 REACTIONS with SODIUM HYDROXIDE SOLUTION

A

CHLORINE: DISPROPORTIONATION REACTION
In cold dilute NaOH => bleach (NaCl + NaClO + H2O)
In hot NaOH => sodium chlorate (V) (NaCl + NaClO3 + H2O)

24
Q

HYDROGEN HALIDES BOILING POINTS

A

HF high (London and hydrogen bond)
Decrease to HCl (no hydrogen bond)
From HCl to HI (increasing London)

25
Q

MAKING HYDROGEN HALIDES

A

Sodium (halide) + sulphuric acid => hydrogen halide + NaHSO4
NaCl + H2SO4 => HCl + NaHSO4
BUT not for iodine; too strong at reducing, so just reduces the sulphur

26
Q

ACIDITY OF HYDROGEN HALIDES

A

ALL STRONG ACIDS EXCEPT HF
HF: ionises, but forms an ion pair, so water ions are bound to F- ion
So less effective as an acid

27
Q

HALIDE IONS AS REDUCING AGENTS

A

RIL
Less electronegative down the group
Better at losing electrons
So better reducers

28
Q

TESTING FOR HALIDE IONS

A
  1. Nitric acid (to prevent formation of other silver salts)
  2. Silver nitrate:
    F- = no ppt
    Cl- = white ppt
    Br- = cream ppt
    I- = yellow ppt
  3. Ammonia solution (dilute)
    AgCl = ppt dissolves
    AgBr and AgI = ppt remains
  4. Ammonia solution (concentrate)
    AgBr = ppt dissolves
    AgI = ppt remains
29
Q

TESTING FOR SULPHATE IONS

A

Use BaCl
BaCl reacts with sulphate to make:
- Barium sulphate (white ppt)
- Halogen chloride

30
Q

TESTING FOR CARBONATE/ HYDROGEN CARBONATES

A
  1. React with HCl
    - Forms CO2 and metal salt (HCl) and water
  2. Test for CO2 using limewater
    - Turns cloudy
31
Q

TESTING FOR AMMONIUM COMPOUNDS

A
  1. Add NaOH
    - Ammonia gas is alkaline, so check for it using damp (red) litmus paper
    - Turns blue if ammonia gas present
32
Q

MANUFACTURING CHLORINE

A
  1. Put in sodium chloride solution (sodium, chloride, OH- and H+ ions present)
  2. Cl- and OH- ions gather at anode
    - Cl is less electronegative than H so it loses electrons more easily so is discharged from solution
    - Two chloride ions each are oxidised and combine to form Cl2 gas
  3. H+ and Na+ ions gather at cathode
    - H is more electronegative than Na so it gains electrons more easily so is discharged from solution
    - Two H+ ions are each reduced to form H2 gas
    - Position of equilibrium shifts and H2O turns into more OH- and H+ ions, leading to congregation of OH- and Na+ ions around cathode: combine to form NaOH
    Note: diaphragm used to separate anode and cathode;
    - If Cl reacts with H2, explosive mixture created and HCl gas
    - If Cl reacts with NaOH, mixture of sodium chloride and sodium chlorate (|) (bleach)
33
Q

GROUP 1 vs GROUP 2 COMPOUNDS: Thermal stability

A

Group 1 = lower ionic charge so less polarising so more stable

34
Q

GROUP 1 CARBONATES: Thermal stability

A

Thermally stable. Don’t decompose

35
Q

GROUP 1 NITRATES: Thermal stability

A

Decompose to form respective nitrite and oxygen

36
Q

GROUP 1 FLAME TESTS

A

Lithium: bright red
Sodium: bright yellow
Potassium: lilac
Rubidium: red/ violet
Caesium: blue/ violet

37
Q

GROUP 2 FLAME TESTS

A

Beryllium: no colour
Magnesium: no colour
Calcium: brick red
Strontium: bright red
Barium: pale green

A-level Chemistry (6 decks)

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