Group 7 Flashcards

1
Q

Group 2 atomic radii down the group?

A

Increases
Additional electron shells

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2
Q

Reactivity down group 7?

A

Decreases
Need to gain an electron
Atomic radius increases down the group due to additional electron shells
Harder to attract an electron

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3
Q

IE down group 7?

A

Decreases
Greater atomic radius
Increased amounts of shielding
Less energy to remove an electron

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4
Q

Boiling point down group 7?

A

Increases
Simple covalent molecules held with VDWS
VDW forces increase down group
More energy required to overcome forces

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5
Q

Oxidising power down group 7?

A

Decreases
Ability to attract electrons decreases
Shielding increases
Atomic radius increases

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6
Q

Cl2 will displace ?

A

Br- and I- ions due to highest oxidising strength

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7
Q

Br2 will displace ?

A

I- ions due to oxidising strength

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8
Q

I2 will displace ??

A

No halide ions due to lowest oxidising strength

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9
Q

Halogens are good ______ agents

A

oxidising

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10
Q

Halides are good _______ agents

A

reducing

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11
Q

Halide ion reducing power down the group?

A

Increases
Electrons easier to lose from larger ions
Due to increased shielding and ionic radii

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12
Q

Sodium fluoride and sulfuric acid reaction

A

NaF + H2SO4 -> NaHSO4 + HF

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13
Q

Sodium chloride and sulphuric acid reaction

A

NaCl + H2SO4 -> NaHSO4 + HCl

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14
Q

Sodium bromide and sulphuric acid reaction

A

NaBr + H2SO4 -> NaHSO4 + HBr
2HBr + H2SO4 -> Br2 + SO2 + 2H2O

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15
Q

Sodium iodide and sulphuric acid reaction

A

NaI + H2SO4 -> NaHSO4 + HI
2HI + H2SO4 -> I2 + SO2 + 2H2O
6HI + SO2 -> H2S + 3I2 + 2H2O

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16
Q

The greater the reducing power, the _______ the reaction and the reason why

A

Longer

The halide is powerful enough to reduce more species

17
Q

The 3 halide ions reacting with silver nitrate

A

Cl- has a white AgCl ppt
Br- has a cream AgBr ppt
I- has a yellow AgI ppt

18
Q

The 3 halide ions compounded with Ag reacting with dilute NH3

A

AgCl ppt’s Cl- ions dissolve, no change in Br- or I- ppts

19
Q

The 3 halide ions compounded with Ag reacting with conc NH3 after dilute NH3

A

AgBr ppt’s Br- ions dissolve, no change in Cl- (already dissolved) or I- ppts

20
Q

Why use ammonia to distinguish simple test for halide results?

A

Ppts may be hard to distinguish

21
Q

Chlorine and water to chlorate ions and chloride ions reaction

A

Cl2 + H2O -> ClO- + Cl- + 2H+
disproportionation

22
Q

Disproportionation reaction

A

a named element is oxidised and reduced

23
Q

Chlorine and water to oxygen and Hydrochloric acid reaction and conditions

A

conditions: UV light
It’s needed over the arrow

2Cl2 + 2H2O -> 4HCl + O2

24
Q

What is chlorine used for in water treatment and why do we use it even if it’s toxic?

A

Killing bacteria
Toxic but benefits of clean, treated water outweigh the risks

25
Q

Bleach production equation and conditions

A

Conditions: cold, aq NaOH

2NaOH + Cl2 -> NaClO + NaCl + H2O

26
Q

Why acidify AgNO3 before test for halides?

A

remove other impurities that can form a precipitate

27
Q

Test for sulfates

A

BaCl2 added, which forms a white ppt of BaSO4

28
Q

Test for hydroxide ions

A

Alkaline
Test with red litmus paper which turns blue
Or universal indicator which turns blue/purple

29
Q

Test for carbonates

A

add HCl
fizzing as CO2 is produced
gas can be collected and bubbled through limewater
limewater turns cloudy

30
Q

What is limewater

A

calcium hydroxide

31
Q

Test for group 2 ions Ca2+, Sr2+ and Ba2+

A

Flame tests

brick red
red
pale green in that order

32
Q

Test for ammonium ions and how to speed it up

A

Basic ammonia gas is given off
Hold red litmus over a petri dish of the substance being tested
Turns blue if NH4OH is present

NaOH can be added to produce the gas faster